Outlook calendar only partially syncing in WorkingHours (Windows + iOS, M365)

Wolf_HAJ

Issue summary:
WorkingHours only displays one single calendar event from my connected Microsoft 365 Outlook calendar, despite the calendar being fully populated and syncing correctly across all other platforms (Outlook desktop, Outlook web, Outlook iOS).

Steps taken to troubleshoot:

Fully removed WorkingHours using Revo Uninstaller Pro (including registry & leftover files)
Reinstalled WorkingHours and reconnected OneDrive and Outlook calendar
Removed/re-authorized permissions via https://myapps.microsoft.com
Reinstalled Outlook app on iPhone
Test calendar entries (recurring, all-day, no attendees) → not imported
Confirmed calendar is selected in WorkingHours under "Show calendar entries in list"
Verified account and calendar visibility in OWA and the new Outlook app (Windows & iOS)

Additional notes:

Calendar name is the default "Calendar" in M365 account ...@DatenschutzTourismus.onmicrosoft.com
No shared calendars, no sub-calendars involved
iOS Outlook calendar sync was previously broken, now fixed — but WorkingHours still doesn't show new or existing events

Expected behavior:
All visible Outlook calendar events should be imported into the WorkingHours timeline view, as per the selected calendar configuration.

Actual behavior:
Only one event (a recurring Friday meeting) is visible in WorkingHours; all other valid events are missing.

Questions:

Are there any known limitations for private, recurring, or Teams/online events?
Does WorkingHours rely on Windows Calendar API or direct Graph API access?

Update:
In the past, all Outlook calendar entries were reliably shown and exported in WorkingHours. I used this regularly for invoicing. This issue seems new – it probably started after a WorkingHours or Outlook update.

WorkingHours version: App Windows App - iOS App
OS + version: 2.12.6.0 PRO
Device model: Lenovo Notebook Windows 11 - iPhone/iPad iOS 18.5

timo

Wolf_HAJ Fully removed WorkingHours using Revo Uninstaller Pro (including registry & leftover files)

Doing just right-click and uninstall in Windows does a full removal of the app without any leftover files. WorkingHours doesn't write in the registry either. Using other methods is likely doing more harm than good. Just as a side note.

Wolf_HAJ Test calendar entries (recurring, all-day, no attendees) → not imported

WorkingHours never showed all-day calendar entries, this is expected behavior.

I haven't made any changes to the Outlook sync in the last couple of months so I am surpised this is a new problem showing for you.

Wolf_HAJ Actual behavior:
Only one event (a recurring Friday meeting) is visible in WorkingHours; all other valid events are missing.

Further up you wrote that recurring events aren't imported, but one actually is shown?

Wolf_HAJ Are there any known limitations for private, recurring, or Teams/online events?

No, the only filter WorkingHours specifies when retrieving is the mentioned "all day" filter and only events from the last 7 days

Wolf_HAJ Does WorkingHours rely on Windows Calendar API or direct Graph API access?

Direct Graph API access

I am unable to reproduce this issue in my tests with a personal Microsoft account.
Are you using a personal account or Microsoft for Business account (you mention https://myapps.microsoft.com so likely a Business account)? Does the problem also happen with a personal account?
Can you give more specific instructions how to create an example event that is not correcly shown in WorkingHours?