This error occurs when the user adds a new "Working Schedule" to the resource, switches to the two-week calendar view, removes all the existing "Working Hours" lines, and then attempts to add a new line under "Working Hours." Steps to reproduce: - Install "resource" module - Settings -> Technical -> Resource -> Working Schedules - New -> Switch to 2 week calendar -> Remove all "Working Hours" lines - Click on Add a line Traceback: ZeroDivisionError float division by zero This commit implements a check for the variable "number_of_days". If the value of "number_of_days" is zero or not found, the function will return zero. This ensures that the function behaves appropriately in cases where the number of days is zero. https://github.com/odoo/odoo/blob/5177e21aea68959eedc73e0034ed984992392dd7/addons/resource/models/resource_calendar.py#L185 sentry - 5108250957 closes odoo/odoo#159844 Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>