diff --git a/addons/event/models/event_event.py b/addons/event/models/event_event.py
index 8ba70e498f8..cd4b33c864e 100644
--- a/addons/event/models/event_event.py
+++ b/addons/event/models/event_event.py
@@ -208,7 +208,7 @@ class EventEvent(models.Model):
             else:
                 event.kanban_state_label = event.stage_id.legend_done
 
-    @api.depends('seats_max', 'registration_ids.state')
+    @api.depends('seats_max', 'registration_ids.state', 'registration_ids.active')
     def _compute_seats(self):
         """ Determine reserved, available, reserved but unconfirmed and used seats. """
         # initialize fields to 0
@@ -225,10 +225,10 @@ class EventEvent(models.Model):
         if self.ids:
             query = """ SELECT event_id, state, count(event_id)
                         FROM event_registration
-                        WHERE event_id IN %s AND state IN ('draft', 'open', 'done')
+                        WHERE event_id IN %s AND state IN ('draft', 'open', 'done') AND active = true
                         GROUP BY event_id, state
                     """
-            self.env['event.registration'].flush(['event_id', 'state'])
+            self.env['event.registration'].flush(['event_id', 'state', 'active'])
             self._cr.execute(query, (tuple(self.ids),))
             res = self._cr.fetchall()
             for event_id, state, num in res:
@@ -496,8 +496,11 @@ class EventEvent(models.Model):
 
     @api.constrains('seats_max', 'seats_available', 'seats_limited')
     def _check_seats_limit(self):
-        if any(event.seats_limited and event.seats_max and event.seats_available < 0 for event in self):
-            raise ValidationError(_('No more available seats.'))
+        for event in self:
+            if event.seats_limited and event.seats_max and event.seats_available < 0:
+                raise ValidationError(_('No more available seats for %s. '
+                                        'Raise the limit or remove some other confirmed registrations first.',
+                                        event.name))
 
     @api.constrains('date_begin', 'date_end')
     def _check_closing_date(self):
diff --git a/addons/event/models/event_registration.py b/addons/event/models/event_registration.py
index e104434459f..18fea786c42 100644
--- a/addons/event/models/event_registration.py
+++ b/addons/event/models/event_registration.py
@@ -96,8 +96,9 @@ class EventRegistration(models.Model):
     @api.constrains('event_id', 'state')
     def _check_seats_limit(self):
         for registration in self:
-            if registration.event_id.seats_limited and registration.event_id.seats_max and registration.event_id.seats_available < (1 if registration.state == 'draft' else 0):
-                raise ValidationError(_('No more seats available for this event.'))
+            event_id = registration.event_id
+            if event_id.seats_limited and event_id.seats_max and event_id.seats_available < (1 if registration.state == 'draft' and event_id.auto_confirm else 0):
+                raise ValidationError(_('There are no more available seats for %s. Raise the limit or remove some other confirmed registrations first.', event_id.name))
 
     @api.constrains('event_ticket_id', 'state')
     def _check_ticket_seats_limit(self):
diff --git a/addons/event/models/event_ticket.py b/addons/event/models/event_ticket.py
index 61ef734e96c..d5207f61f08 100644
--- a/addons/event/models/event_ticket.py
+++ b/addons/event/models/event_ticket.py
@@ -91,7 +91,7 @@ class EventTicket(models.Model):
             else:
                 ticket.sale_available = True
 
-    @api.depends('seats_max', 'registration_ids.state')
+    @api.depends('seats_max', 'registration_ids.state', 'registration_ids.active')
     def _compute_seats(self):
         """ Determine reserved, available, reserved but unconfirmed and used seats. """
         # initialize fields to 0 + compute seats availability
@@ -107,10 +107,10 @@ class EventTicket(models.Model):
             }
             query = """ SELECT event_ticket_id, state, count(event_id)
                         FROM event_registration
-                        WHERE event_ticket_id IN %s AND state IN ('draft', 'open', 'done')
+                        WHERE event_ticket_id IN %s AND state IN ('draft', 'open', 'done') AND active = true
                         GROUP BY event_ticket_id, state
                     """
-            self.env['event.registration'].flush(['event_id', 'event_ticket_id', 'state'])
+            self.env['event.registration'].flush(['event_id', 'event_ticket_id', 'state', 'active'])
             self.env.cr.execute(query, (tuple(self.ids),))
             for event_ticket_id, state, num in self.env.cr.fetchall():
                 results.setdefault(event_ticket_id, {})[state_field[state]] = num
@@ -129,8 +129,12 @@ class EventTicket(models.Model):
 
     @api.constrains('seats_available', 'seats_max')
     def _constrains_seats_available(self):
-        if any(record.seats_max and record.seats_available < 0 for record in self):
-            raise ValidationError(_('No more available seats for this ticket.'))
+        for record in self:
+            if record.seats_max and record.seats_available < 0:
+                raise ValidationError(
+                    _('No more available seats for the ticket %s (%s). '
+                      'Raise the limit or remove some other confirmed registrations first.',
+                      record.name, record.event_id.name))
 
     def _get_ticket_multiline_description(self):
         """ Compute a multiline description of this ticket. It is used when ticket
diff --git a/addons/event/static/src/scss/event.scss b/addons/event/static/src/scss/event.scss
index 703f90377e8..439b7a125da 100644
--- a/addons/event/static/src/scss/event.scss
+++ b/addons/event/static/src/scss/event.scss
@@ -23,6 +23,32 @@
             min-height: 80px;
         }
     }
+    .oe_kanban_card_ribbon {
+        min-height: 95px;
+        .ribbon {
+            &::before, &::after {
+                display: none;
+            }
+            span {
+                padding: 5px;
+                font-size: small;
+                z-index: 0;
+            }
+        }
+        .ribbon-top-right {
+            margin-top: -1px;
+            span {
+                left: 7px;
+                right: 30px;
+                height: 25px;
+                top: 18px;
+            }
+        }
+        // Used for "Group By"
+        div.row {
+            min-height: 95px;
+        }
+    }
 }
 
 .o_event_registration_view_tree {
diff --git a/addons/event/tests/test_event_internals.py b/addons/event/tests/test_event_internals.py
index e02a42aedf5..2b1b3b9b546 100644
--- a/addons/event/tests/test_event_internals.py
+++ b/addons/event/tests/test_event_internals.py
@@ -486,12 +486,13 @@ class TestEventData(TestEventInternalsCommon):
 
         # create registration in order to check the seats computation
         self.assertTrue(event.auto_confirm)
-        for x in range(5):
-            reg = self.env['event.registration'].create({
-                'event_id': event.id,
-                'name': 'reg_open',
-            })
-            self.assertEqual(reg.state, 'open')
+        reg_open_multiple = self.env['event.registration'].create([{
+            'event_id': event.id,
+            'name': 'reg_open',
+        } for _ in range(5)])
+        self.assertEqual(set(reg_open_multiple.mapped('state')), {'open'})
+        reg_open = reg_open_multiple[0]
+
         reg_draft = self.env['event.registration'].create({
             'event_id': event.id,
             'name': 'reg_draft',
@@ -508,6 +509,38 @@ class TestEventData(TestEventInternalsCommon):
         self.assertEqual(event.seats_used, 1)
         self.assertEqual(event.seats_expected, 7)
 
+        # ------------------------------------------------------------
+        # (UN-)ARCHIVING REGISTRATIONS
+        # ------------------------------------------------------------
+
+        # Archiving and seats availability
+        reg_open.action_archive()
+        self.assertEqual(event.seats_reserved, 4)
+        self.assertEqual(event.seats_available, event.event_type_id.seats_max - 5)
+        self.assertEqual(event.seats_expected, 6)
+
+        reg_draft.action_archive()
+        self.assertEqual(event.seats_unconfirmed, 0)
+        self.assertEqual(event.seats_available, event.event_type_id.seats_max - 5)
+        self.assertEqual(event.seats_expected, 5)
+
+        # Un-archiving confirmed seats requires available seat(s)
+        reg_open.action_unarchive()
+        self.assertEqual(event.seats_reserved, 5)
+        self.assertEqual(event.seats_available, event.event_type_id.seats_max - 6)
+        self.assertEqual(event.seats_expected, 6)
+
+        reg_draft.action_unarchive()
+        self.assertEqual(event.seats_unconfirmed, 1)
+        self.assertEqual(event.seats_available, event.event_type_id.seats_max - 6)
+        self.assertEqual(event.seats_expected, 7)
+
+        reg_open.action_archive()
+        event.write({'seats_max': 5})
+        # It is not possible to unarchive confirmed seat if event is full
+        with self.assertRaises(exceptions.ValidationError):
+            reg_open.action_unarchive()
+
 
 class TestEventRegistrationData(TestEventInternalsCommon):
 
@@ -609,19 +642,21 @@ class TestEventTicketData(TestEventInternalsCommon):
     @users('user_eventmanager')
     def test_event_ticket_fields(self):
         """ Test event ticket fields synchronization """
+        INITIAL_TICKET_SEATS_MAX = 30
         event = self.event_0.with_user(self.env.user)
         event.write({
             'event_ticket_ids': [
                 (5, 0),
                 (0, 0, {
                     'name': 'First Ticket',
-                    'seats_max': 30,
+                    'seats_max': INITIAL_TICKET_SEATS_MAX,
                 }), (0, 0, {  # limited in time, available (01/10 (start) < 01/31 (today) < 02/10 (end))
                     'name': 'Second Ticket',
                     'start_sale_datetime': datetime(2020, 1, 10, 0, 0, 0),
                     'end_sale_datetime': datetime(2020, 2, 10, 23, 59, 59),
                 })
             ],
+            'auto_confirm': False  # to interact with registrations states
         })
         first_ticket = event.event_ticket_ids.filtered(lambda t: t.name == 'First Ticket')
         second_ticket = event.event_ticket_ids.filtered(lambda t: t.name == 'Second Ticket')
@@ -677,6 +712,67 @@ class TestEventTicketData(TestEventInternalsCommon):
         self.assertFalse(second_ticket.sale_available)
         self.assertTrue(second_ticket.is_expired)
 
+        # ------------------------------------------------------------
+        # (UN-)ARCHIVING TICKET REGISTRATIONS
+        # ------------------------------------------------------------
+
+        # Archiving and seats availability
+        reg_draft_multiple = self.env['event.registration'].create([{
+            'event_id': event.id,
+            'name': f'reg_draft #{idx}',
+            'event_ticket_id': first_ticket.id,
+        } for idx in range(3)])
+        reg_draft = reg_draft_multiple[0]
+
+        reg_open = self.env['event.registration'].create({
+            'event_id': event.id,
+            'name': 'reg_open',
+            'event_ticket_id': first_ticket.id,
+            'state': 'open'
+        })
+
+        reg_done = self.env['event.registration'].create({
+            'event_id': event.id,
+            'name': 'reg_done',
+            'event_ticket_id': first_ticket.id,
+            'state': 'done'
+        })
+
+        self.assertEqual(first_ticket.seats_unconfirmed, 3)
+        self.assertEqual(first_ticket.seats_reserved, 1)
+        self.assertEqual(first_ticket.seats_used, 1)
+        self.assertEqual(first_ticket.seats_available, INITIAL_TICKET_SEATS_MAX - 2)
+
+        reg_done.action_archive()
+        self.assertEqual(first_ticket.seats_used, 0)
+        self.assertEqual(first_ticket.seats_available, INITIAL_TICKET_SEATS_MAX - 1)
+
+        reg_open.action_archive()
+        self.assertEqual(first_ticket.seats_reserved, 0)
+        self.assertEqual(first_ticket.seats_available, INITIAL_TICKET_SEATS_MAX)
+
+        reg_draft.action_archive()
+        self.assertEqual(first_ticket.seats_unconfirmed, 2)
+
+        # Un-archiving confirmed/done seats requires available seat(s)
+        reg_open.action_unarchive()
+        self.assertEqual(first_ticket.seats_reserved, 1)
+        self.assertEqual(first_ticket.seats_available, INITIAL_TICKET_SEATS_MAX - 1)
+
+        reg_done.action_unarchive()
+        self.assertEqual(first_ticket.seats_used, 1)
+        self.assertEqual(first_ticket.seats_available, INITIAL_TICKET_SEATS_MAX - 2)
+
+        reg_draft.action_unarchive()
+        self.assertEqual(first_ticket.seats_unconfirmed, 3)
+        self.assertEqual(first_ticket.seats_available, INITIAL_TICKET_SEATS_MAX - 2)
+
+        reg_open.action_archive()
+        first_ticket.write({'seats_max': 1})
+        # It is not possible to unarchive confirmed seat if ticket is fully booked
+        with self.assertRaises(exceptions.ValidationError):
+            reg_open.action_unarchive()
+
 
 class TestEventTypeData(TestEventInternalsCommon):
 
diff --git a/addons/event/views/event_views.xml b/addons/event/views/event_views.xml
index 2dfb2c4c691..83fe16fc936 100644
--- a/addons/event/views/event_views.xml
+++ b/addons/event/views/event_views.xml
@@ -30,7 +30,7 @@
                                    <field name="has_seats_limitation"/>
                                    <span attrs="{'invisible': [('has_seats_limitation', '=', False)], 'required': [('has_seats_limitation', '=', False)]}">
                                        to <field name="seats_max" class="oe_inline"/>
-                                       Attendees
+                                       Confirmed Attendees
                                    </span>
                                </div>
                                <div colspan="2" class="o_checkbox_optional_field">
@@ -206,6 +206,7 @@
                                 <field name="seats_expected" widget="statinfo" string="Attendees"/>
                             </button>
                         </div>
+                        <field name="active" invisible="1"/>
                         <field name="legend_blocked" invisible="1"/>
                         <field name="legend_normal" invisible="1"/>
                         <field name="legend_done" invisible="1"/>
@@ -238,7 +239,7 @@
                                 <div colspan="2" class="o_checkbox_optional_field">
                                     <label for="seats_limited" string="Limit Registrations"/>
                                     <field name="seats_limited"/>
-                                    <span attrs="{'invisible': [('seats_limited', '=', False)], 'required': [('seats_limited', '=', False)]}">to <field name="seats_max" class="oe_inline"/> Attendees</span>
+                                    <span attrs="{'invisible': [('seats_limited', '=', False)], 'required': [('seats_limited', '=', False)]}">to <field name="seats_max" class="oe_inline"/> Confirmed Attendees</span>
                                 </div>
                                 <field name="auto_confirm"/>
                             </group>
@@ -445,7 +446,7 @@
                     <separator/>
                     <filter string="Start Date" name="start_date" date="date_begin"/>
                     <separator/>
-                    <filter string="Archived" name="inactive" domain="[('active', '=', False)]"/>
+                    <filter string="Archived" name="filter_inactive" domain="[('active', '=', False)]"/>
                     <separator/>
                     <filter invisible="1" string="Late Activities" name="activities_overdue"
                         domain="[('my_activity_date_deadline', '&lt;', context_today().strftime('%Y-%m-%d'))]"
@@ -519,6 +520,7 @@
                 <tree string="Registration" multi_edit="1" sample="1"
                       expand="1" default_order="create_date desc"
                       class="o_event_registration_view_tree">
+                    <field name="active" invisible="1"/>
                     <field name="create_date" optional="show" string="Registration Date"/>
                     <field name="name"/>
                     <field name="partner_id" optional="hide"/>
@@ -533,11 +535,13 @@
                            decoration-muted="state == 'cancel'" widget="badge"/>
                     <field name="company_id" groups="base.group_multi_company" optional="hide"/>
                     <field name="message_needaction" invisible="1"/>
-                    <button name="action_confirm" string="Confirm" states="draft" type="object" icon="fa-check"/>
-                    <button name="action_set_done" string="Mark as Attending" states="open" type="object" icon="fa-level-down"/>
-                    <button name="action_cancel" string="Cancel"
-                            states="draft,open" type="object"
-                            class="o_btn_cancel_registration" icon="fa-times"/>
+                    <button name="action_confirm" string="Confirm" type="object" icon="fa-check"
+                            attrs="{'invisible': ['|', ('active', '=', False), ('state', '!=', 'draft')]}"/>
+                    <button name="action_set_done" string="Mark as Attending" type="object" icon="fa-level-down"
+                            attrs="{'invisible': ['|', ('active', '=', False), ('state', '!=', 'open')]}"/>
+                    <button name="action_cancel" string="Cancel" type="object"
+                            class="o_btn_cancel_registration" icon="fa-times"
+                            attrs="{'invisible': ['|', ('active', '=', False), '&amp;', ('state', '!=', 'open'), ('state', '!=', 'draft')]}"/>
                     <field name="activity_exception_decoration" widget="activity_exception"/>
                 </tree>
             </field>
@@ -548,16 +552,23 @@
             <field name="model">event.registration</field>
             <field name="arch" type="xml">
                 <form string="Event Registration">
+                    <field name="active" invisible="1"/>
                     <header>
-                        <button name="action_send_badge_email" string="Send by Email" type="object" states="open,done" class="oe_highlight"/>
-                        <button name="action_confirm" string="Confirm" states="draft" type="object" class="oe_highlight"/>
-                        <button name="action_set_done" string="Attended" states="open" type="object" class="oe_highlight"/>
-                        <button name="action_set_draft" string="Set To Unconfirmed" states="cancel,done" type="object" />
-                        <button name="action_cancel" string="Cancel Registration" states="draft,open" type="object"/>
+                        <button name="action_send_badge_email" string="Send by Email" type="object" class="oe_highlight"
+                                attrs="{'invisible': ['|', ('active', '=', False), '&amp;', ('state', '!=', 'open'), ('state', '!=', 'done')]}"/>
+                        <button name="action_confirm" string="Confirm" type="object" class="oe_highlight"
+                                attrs="{'invisible': ['|', ('active', '=', False), ('state', '!=', 'draft')]}"/>
+                        <button name="action_set_done" string="Attended" type="object" class="oe_highlight"
+                                attrs="{'invisible': ['|', ('active', '=', False), ('state', '!=', 'open')]}"/>
+                        <button name="action_set_draft" string="Set To Unconfirmed" type="object"
+                                attrs="{'invisible': ['|', ('active', '=', False), '&amp;', ('state', '!=', 'cancel'), ('state', '!=', 'done')]}"/>
+                        <button name="action_cancel" string="Cancel Registration" type="object"
+                                attrs="{'invisible': ['|', ('active', '=', False), '&amp;', ('state', '!=', 'open'), ('state', '!=', 'draft')]}"/>
                         <field name="state" nolabel="1" colspan="2" widget="statusbar" statusbar_visible="draft,open,done"/>
                     </header>
                     <sheet string="Registration">
                         <div class="oe_button_box" name="button_box"/>
+                        <widget name="web_ribbon" text="Archived" bg_color="bg-danger" attrs="{'invisible': [('active', '=', True)]}"/>
                         <group>
                             <group string="Attendee" name="attendee">
                                 <field class="o_text_overflow" name="name"/>
@@ -605,39 +616,47 @@
                     <field name="state"/>
                     <field name="email"/>
                     <field name="event_ticket_id"/>
+                    <field name="active" invisible="1"/>
                     <templates>
                         <t t-name="event_attendees_kanban_icons_desktop">
                             <div class="d-none d-md-block h-100">
                                 <div id="event_attendees_kanban_icons_desktop" class="h-100 float-right p-2 d-flex align-items-end flex-column">
-                                    <a class="btn btn-md btn-primary" string="Confirm Registration" name="action_confirm" type="object" states="draft" role="button">
-                                        <i class="fa fa-check" role="img" aria-label="Confirm button" title="Confirm Registration"/>
-                                    </a>
-                                    <a class="btn btn-md btn-primary" string="Confirm Attendance" name="action_set_done" type="object" states="open" role="button">
-                                        <i class="fa fa-user-plus" role="img" aria-label="Attended button" title="Confirm Attendance"/>
-                                    </a>
-                                    <span class="text-muted" states="done">Attended</span>
-                                    <span class="text-muted" states="cancel">Canceled</span>
+                                    <t t-if="record.active.raw_value">
+                                        <a class="btn btn-md btn-primary" string="Confirm Registration" name="action_confirm" type="object" states="draft" role="button">
+                                            <i class="fa fa-check" role="img" aria-label="Confirm button" title="Confirm Registration"/>
+                                        </a>
+                                        <a class="btn btn-md btn-primary" string="Confirm Attendance" name="action_set_done" type="object" states="open" role="button">
+                                            <i class="fa fa-user-plus" role="img" aria-label="Attended button" title="Confirm Attendance"/>
+                                        </a>
+                                        <span class="text-muted" states="done">Attended</span>
+                                        <span class="text-muted" states="cancel">Canceled</span>
+                                    </t>
                                 </div>
                             </div>
                         </t>
                         <t t-name="event_attendees_kanban_icons_mobile">
                             <div id="event_attendees_kanban_icons_mobile" class="d-md-none h-100 pl-4">
-                                <a class="btn btn-primary d-flex justify-content-center align-items-center h-100 w-100"
-                                    string="Confirm Registration" name="action_confirm" type="object" states="draft" role="button">
-                                    <i class="fa fa-check fa-3x" role="img" aria-label="Confirm button" title="Confirm Registration"/>
-                                </a>
-                                <a class="btn btn-primary d-flex justify-content-center align-items-center h-100 w-100"
-                                    string="Confirm Attendance" name="action_set_done" type="object" states="open" role="button">
-                                    <i class="fa fa-user-plus fa-3x" role="img" aria-label="Attended button" title="Confirm Attendance"/>
-                                </a>
-                                <div class="d-flex justify-content-center align-items-center h-100 w-100">
-                                    <span class="text-muted" states="done" >Attended</span>
-                                    <span class="text-muted" states="cancel" >Canceled</span>
-                                </div>
+                                <t t-if="record.active.raw_value">
+                                    <a class="btn btn-primary d-flex justify-content-center align-items-center h-100 w-100"
+                                        string="Confirm Registration" name="action_confirm" type="object" states="draft" role="button">
+                                        <i class="fa fa-check fa-3x" role="img" aria-label="Confirm button" title="Confirm Registration"/>
+                                    </a>
+                                    <a class="btn btn-primary d-flex justify-content-center align-items-center h-100 w-100"
+                                        string="Confirm Attendance" name="action_set_done" type="object" states="open" role="button">
+                                        <i class="fa fa-user-plus fa-3x" role="img" aria-label="Attended button" title="Confirm Attendance"/>
+                                    </a>
+                                    <div class="d-flex justify-content-center align-items-center h-100 w-100">
+                                        <span class="text-muted" states="done" >Attended</span>
+                                        <span class="text-muted" states="cancel" >Canceled</span>
+                                    </div>
+                                </t>
                             </div>
                         </t>
                         <t t-name="kanban-box">
-                            <div class="oe_kanban_global_click o_event_registration_kanban container-fluid p-0">
+                            <div t-attf-class="#{!record.active.raw_value ? 'oe_kanban_card_ribbon' : ''} oe_kanban_global_click o_event_registration_kanban container-fluid p-0">
+                                <div t-if="!record.active.raw_value" class="ribbon ribbon-top-right">
+                                    <span class="bg-danger">Archived</span>
+                                </div>
                                 <div class="row h-100">
                                     <div class="col-9 pr-0">
                                         <div class="oe_kanban_content h-100">
@@ -719,6 +738,8 @@
                     <field name="event_id"/>
                     <field name="partner_id"/>
                     <field name="company_id"/>
+                    <separator/>
+                    <filter string="Archived" name="filter_inactive" domain="[('active', '=', False)]"/>
                     <filter invisible="1" string="Late Activities" name="activities_overdue"
                         domain="[('my_activity_date_deadline', '&lt;', context_today().strftime('%Y-%m-%d'))]"
                         help="Show all records which has next action date is before today"/>