Outlook calendar freezes, does not respond when clicking on any calendar item and crashes outlook

Hello Gordon S,

My name is Chloe, and I will be working with you to get this fully resolved. Based on the details provided earlier, I suggest we try creating a new user profile to rule out any underlying configuration issues.

Before we do that, we should ensure your data is safe: 

Step 1: Back up Your Calendar Data 

1. Open Outlook and go to your Calendar. 
2. Go to the View tab on the top ribbon, click Change View, and select List. 
3. If Outlook remains stable in List view, please perform a backup: 
4. Go to File > Open & Export > Import/Export. 
5. Select Export to a file, then Outlook Data File (.pst). 
6. Select your Calendar folder, ensure "Include subfolders" is checked, and save the file to your Desktop. 

Step 2: Create a New Outlook Profile 

1. Close Outlook. Open the Control Panel and search for Mail. 
2. Click Show Profiles > Add. 
3. Type a new name (e.g., "Outlook Test") and click OK. 
4. Follow the prompts to add your email account again. 
5. Under "When starting Microsoft Outlook, use this profile," select Prompt for a profile to be used and click OK. 
6. Restart Outlook and choose your new profile to see if the crashing persists. 

If a new profile does not resolve the issue, it is highly recommended to roll back Office to a previous, stable build. 

Step 1: Disable Automatic Updates 

This prevents Outlook from reinstalling the problematic update overnight. 

1. Open any Office app that is not crashing (like Word or Excel). 
2. Go to File > Account. 
3. Under Product Information, click Update Options > Disable Updates. 

Step 2: Execute the Rollback Command 

1. Close all Office applications. 
2. Click the Windows Start button, type cmd, right-click Command Prompt, and select Run as administrator. 
3. Copy and paste the following command exactly, then press Enter: 
4. "C:\Program Files\Common Files\microsoft shared\ClickToRun\officec2rclient.exe" /update user updatetoversion=16.0.17328.20142 
5. An Office window will appear saying it is "Downloading Office updates." Please let this process complete. 
6. Once finished, open Outlook. It will now be running on a stable build from late February. 

Note: If the rollback stabilizes your calendar, I recommend leaving updates disabled for roughly 30 to 45 days. This allows the engineering team enough time to release a patched build. 

I truly hope these steps help you regain a stable calendar. Please let us know if the steps help.

Hi @Gordon S

Can you please provide your exact Outlook version? You can check this in File > Office account > About Outlook.

May I ask if you are using Exchange, IMAP or POP account?

If you are using Exchange, can you use the calendar via https://outlook.office.com/mail/?

If yes, the issue might be from Classic Outlook itself. Recently there is an incident where Outlook crashes when older builds of classic Outlook are using the newest version of the Teams Meeting Add-In build 1.26.02603. However, this issue has been fixed with the newest Teams version.

Classic Outlook crashes and opens in Safe Mode starting March 12 2026 - Microsoft Support

Can you check your Teams version and Team add-in meeting as well? You can check this in Settings > Apps > Installed apps.

What you can try now is:

• Open Outlook in safe mode - Microsoft Support and uncheck any suspicious add-in.
• Update Teams to the latest version.
• Rebuild .ost file: Close Outlook > Press Windows + R > Type in %LOCALAPPDATA%\Microsoft\Outlook\ > Look for your email address and delete it > Restart Outlook.

If the issue persists, please provide your Outlook, Teams, Teams add-in version.

I look forward for your reply.

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Follow these steps in order, testing the calendar after each step:

1. Start Outlook in safe mode to rule out add-ins
   • Close Outlook.
   • Press Windows + R, type outlook.exe /safe, and select OK.
   • Open the Calendar and click items.
   • If the calendar works in safe mode, disable COM add-ins:
     1. In Outlook, select File > Options > Add-ins.
     2. At the bottom, next to Manage, select COM Add-ins and then Go.
     3. Clear all check boxes to disable add-ins and select OK.
     4. Restart Outlook normally and test the calendar.
     5. Re-enable add-ins one by one, restarting Outlook each time, until the problem returns; leave the problematic add-in disabled.
2. Repair Outlook data files (calendar lives in the same store)
   • Close Outlook.
   • Run the Inbox Repair Tool (SCANSPST.EXE) as described in Repair Outlook Data Files (.pst and .ost).
   • Repair the data file used by the affected profile, then reopen Outlook and test the calendar.
3. Create and test with a new Outlook profile
   • Create a new profile using the steps in Create an Outlook profile.
   • When done:
     1. Close Outlook.
     2. Hold Shift and start Outlook.
     3. In Choose Profile, select the new profile and choose OK.
   • Configure the same accounts, then test the calendar. If the calendar works in the new profile, the original profile is corrupted; continue using the new profile.
4. Install the latest Windows and Office updates
   • Ensure Windows and Microsoft 365/Office are fully updated, as fixes for freezes and crashes are released regularly.
   • For Office updates, see Install Office updates.
5. If the issue is calendar-specific and persists
   • Run the Outlook Calendar diagnostic using Microsoft Support and Recovery Assistant as described in Scan Outlook calendar by using Microsoft Support and Recovery Assistant. This will scan for calendar configuration and item issues (permissions, free/busy, delegates, automatic booking, and known calendar problems) and attempt to fix them.

If, after these steps, Outlook still crashes only when interacting with calendar items, collect details (Outlook version, Windows build, whether the issue occurs in a new profile and in safe mode) and provide them when opening a support case, as the behavior may be tied to a specific recent update.

References:

• Outlook for Windows not responding, hangs, freezes, or stops working
• Troubleshoot Outlook for Windows issues
• Outlook not responding, stuck at "Processing," stopped working, or freezes
• Outlook crashes or stops responding when used with Office 365
• Scan Outlook calendar by using Microsoft Support and Recovery Assistant