diff --git a/addons/mail/static/src/models/attachment.js b/addons/mail/static/src/models/attachment.js
index 294157fb350..a130c981d48 100644
--- a/addons/mail/static/src/models/attachment.js
+++ b/addons/mail/static/src/models/attachment.js
@@ -15,6 +15,9 @@ registerModel({
          */
         convertData(data) {
             const data2 = {};
+            if ('checksum' in data) {
+                data2.checksum = data.checksum;
+            }
             if ('filename' in data) {
                 data2.filename = data.filename;
             }