Calendar can’t save the event … to the Exchange server. There was an error attempting to send your changes to the exchange server” – I faced this error in iCal for my Exchange calendar with three options (Revert to Server, Try Again or Ignore) and was unable to Save Calendar to Exchange Office 365 in iCal in OS X 10.10 Yosemite . I finally found out that removing the Time Zone Support cache can solve the problem.

It is unable to Save Calendar to Exchange Office 365 in iCal in OS X

How to delete the Time Zone Support cache in Mac OS X?

Firstly, you should check to make sure that your hard disk is visible in Finder: Open Finder > Preferences > Check on ‘Hard disks‘ under Sidebar tab.

Check Hard disk in Finder Preference

  • Access your “Macintosh HD” from Finder window > Open Library:

Clear Time Zone Support cache in Mac OS X

  • Open Cache folder and delete the Time Zone Support cache file:

Time Zone Support cache in Mac OS XNot only this error, some other communication issues with an Exchange server should be solved via this tip.

  • Lisa Berelson

    I rebooted after following instructions. This solution did not work for me in OS10.9.5.

  • DazB

    I don’t have the file shown in this tutorial within the Caches directory.

  • Ken Wilson

    This solution just worked for me with macOS Sierra 10.12 public beta.

  • Thanks for the idea. Unfortunately, this solution did not work for me on MacOS Sierra Version 10.12.5