Q: iCalendar gets stuck

Hello Badgerfan33,

Thank you for being part of the Apple Community!

Based on what you stated, it seems you may be having issues with the Calendar app.  I have multiple calandars myself and know how important it is to keep them all synced and working correctly.

The first thing I recommend is to backup everything that is on the computer. Nothing I am going to suggest should cause any data loss, but it is always a good idea to have a backup.  Your computer has software on it called Time Machine.  It is fantastic software for backing up your computer.  Information on how to use Time Machine is available here:

Use Time Machine to back up or restore your Mac.

Once you have a good backup, be sure that the computer is running the latest version of OS X.  The current version is 10.11.6.  You can check what version the computer is running by clicking on the Apple Logo in the upper left corner, then click on About this Mac.  The window that opens should say "OS X El Capitan" with the Version number beneath it.  If it is running something than El Capitan, follow these instructions: 

Upgrade to OS X El Capitan

Test the Calandar app again once the OS X is updated to the latest version.  If the message does not appear, then you should be all set.  If the error message returns, continue on to the next steps.

If the system is already running 10.11.6, then follow these steps:

1. Quit the Calendar app.
2. Go to the Apple Menu in the upper left corner of the screen.  Click on System Preferences > iCloud.  Uncheck Calendars and Reminders.
3. It will ask you "If you want to delete reminder events and calendars from your system". Choose yes. You should have  an up-to-date copy iCloud.
4. Launch Calendar app. It should no longer display the “Moving calendars to server account” error message.
5. To add the iCloud account back to the Calendar app, click on Calendar > Add Account > iCloud.  Sign in with your Apple ID and password.
6. It may take a few minutes for the Calendar to update.

This should keep the error message from appearing again.

Cheers!

Hey Badgerfan33,

The next thing I would recommend would be to set up a test user account and see if you receive the same error there.  This will tell you whether the issue is system wide, or isolated to a particular user.  

You can find instructions on how to test in another user account here:

How to test an issue in another user account on your Mac

Have a great day!

Hey Badgerfan33,

Since everything worked correctly in the test user, that tells us that there is something in the main user account that is creating the problem.

I would recommend removing all the items from your login startup.  

1. Choose Apple menu > System Preferences, then click Users & Groups.

2. Click your account name below Current User, then click Login Items.

    

   Make a list of the login items—you’ll need to remember them later.

3. Select all of the login items, then click the Remove button . 

4. Choose Apple menu > Restart.

5. If this solves the problem, open Users & Groups preferences again, add the login items one at a time, and restart your Mac after adding each one. 

    

   When the problem occurs again, follow the steps above to remove only the last login item you added.

OS X El Capitan: If you think you have incompatible login items

Cheers!