Upgrade to Microsoft FixTechGuide Windows update Outlook fix Edge to take advantage of the latest features, security updates, and technical support. You can start Outlook in safe mode, disable your add-ins, and then try to open Outlook normally. The folder may have been deleted or the server where the folder is stored may be unavailable. To access the filtering options faster, add them to your Quick Access Toolbar.

• Third-party add-ins are among the most common culprits for Outlook not opening properly.
• If you're using Outlook 2010, Outlook 2013 or Outlook 2016, uninstall and re-install iCloud to resolve this issue.
• For more information about when builds are available for their respective channels, go to Update history for Microsoft 365.
• We're investigating the issues and will update this page when a fix is available.

Outlook Known issues in October 2020 updates

If you can't open Outlook, or Outlook disappears or crashes, one of your add-ins may be to blame or you may need to update Outlook. Right-click the folder, and then click Properties to check your permissions for the folder. See Fix Outlook and Office365 Sync Issues the folder owner or your administrator to change your permissions. There is currently no option to revert to the prior behavior, but we would love to hear your feedback to help us with future designs.

Outlook known issues in the January 2019 updates

Auto-archive, sending and receiving a very large attachment, or running Troubleshoot Office 365 Sync and Login Issues some of the other mailbox tools can all be done in the background. Check the status bar at the bottom of the screen to see if another process is running. If so, wait a short time (usually two or three minutes) to see if Outlook starts working again. To access the calendar shared with your Microsoft 365 for business account, you'll need to accept the invitation from Outlook on the web, iOS, or Android.

Troubleshoot Outlook for Windows issues

Most startup failures arise from minor configuration mismatches or outdated components. Following the above steps—from safe mode diagnostics to repairing data files—will restore functionality in most cases. FixTechGuide’s free email diagnostic tools automate error detection by scanning your configuration files, registry entries, and mail protocols. The platform validates SMTP, IMAP, and POP3 settings against verified databases to identify version mismatches or broken profiles introduced after system updates.

Outlook Known issues in March 2025 updates

Stay updated, back up regularly, and enjoy uninterrupted productivity in your Outlook workspace. Online Repair reinstalls Outlook components while preserving your data, resolving DLL and registry mismatches that prevent startup. This process checks for structural issues and automatically fixes them. Occasionally, classic Outlook tries to run a process in the background.



Third-party add-ins are among the most common culprits for Outlook not opening properly. Safe Mode allows you to start Outlook with all extensions temporarily disabled. The only other change to the Exchange Server was a certificate update for IIS. This is a standard DigiCert wildcard cert that we have replaced every year with no issues.