[GH-ISSUE #452] Events not synchronized between Outlook and source calendar in some cases #433

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opened 2026-02-25 20:31:37 +03:00 by kerem · 0 comments

kerem commented

2026-02-25 20:31:37 +03:00

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Originally created by @ALacroix68 on GitHub (Jun 4, 2025).
Original GitHub issue: https://github.com/aluxnimm/outlookcaldavsynchronizer/issues/452

Hello,

First of all, thanks for your work on this tool !

I founded a case where caldav synchronizer doesn't works great, this causes a desynchronization with the source calendar.

Configurations :

Caldav version : 4.5.0.0
Outlook version : Version 2504 Build 18730.20186
Activate caldav option "Synchronize items immediatly after change"
Activate caldav option "Use GlobalAppointmentID for UID attribute"

Here is an example to illustrate the bug, it will be easier :

Send an invitation from a Microsoft address to the address synchronized in Outlook
On the Outlook app stay on the mail view. Outlook will create his own event when receiving the email
From the mail, accept the invitation by the Outlook button with "Send the response now"

Go to the calendar view, launch a caldav synchronization
Caldav calls to get events from source. Given that the source calendar create the event aswell on his side, he sees that the source already have the event, so it don't call an update
The event is accepted on Outlook but not on source calendar

I think that caldav synchronization should call an update even if we send the UID of the event, because it's possible that changes has been done on Outlook side. What do you think ?

I stay available for further informations.

Originally created by @ALacroix68 on GitHub (Jun 4, 2025). Original GitHub issue: https://github.com/aluxnimm/outlookcaldavsynchronizer/issues/452 Hello, First of all, thanks for your work on this tool ! I founded a case where caldav synchronizer doesn't works great, this causes a desynchronization with the source calendar. Configurations : - Caldav version : 4.5.0.0 - Outlook version : Version 2504 Build 18730.20186 - Activate caldav option "Synchronize items immediatly after change" - Activate caldav option "Use GlobalAppointmentID for UID attribute" Here is an example to illustrate the bug, it will be easier : - Send an invitation from a Microsoft address to the address synchronized in Outlook - On the Outlook app stay on the mail view. Outlook will create his own event when receiving the email - From the mail, accept the invitation by the Outlook button with "Send the response now" ![Image](https://github.com/user-attachments/assets/7e6996d7-ffed-48c6-9b7c-67bf578bd42c) - Go to the calendar view, launch a caldav synchronization - Caldav calls to get events from source. Given that the source calendar create the event aswell on his side, he sees that the source already have the event, so it don't call an update - The event is accepted on Outlook but not on source calendar I think that caldav synchronization should call an update even if we send the UID of the event, because it's possible that changes has been done on Outlook side. What do you think ? I stay available for further informations.