When iCloud breaks your Outlook

Recently we saw an increasing number of tickets where user complained about issues retrieving Free/Busy data while scheduling a meeting or for shared calendar.

When trying to schedule a meeting you would see only hash marks

No F/B data in Scheduling Assistant

Symptoms

After installing iCloud users cannot retrieve Free/Busy data or content from shared calendar. On shared calendar user will see “no connection”

At the same time Outlook Connection Status shows an established connection (the procedure is explained here). Also a Fiddler trace and parsing the MapiHttp logs with Get-MAPIStats.ps1 shows connectivity and no server-side errors.

Workaround

After some troubleshooting my co-worker figured out that lately iCloud was installed, which comes with an add-in for Outlook. The issue was resolved as soon as the add-in was disabled. But I wanted to know what exactly the issue is as others could use iCloud without issues.

One thing I realized was the formating after the installation

This reminded me checking my regional settings

My Windows 10 is English, but I’ve chosen German for formating. After I switched to “Match Windows display language (recommended)” everything started working.

The other solutions to fix F/B and shared calendar data access are:

• disable the Outlook add-in (steps are described here)
• uninstall iCloud

Conclusion

I’m wondering how something like this is possible these days. I wrote above Workaround and not Resolution on purpose as the only resolution can be done by the developers of iCloud. I hope this helps and you can save time with troubleshooting.