Outlook won't open on my Windows 10 PC have Microsoft 365 and do the Repair and restart but it doesn't work except occasionally if I "Run as administrator" it will open but then will stop working Microsoft Q&A

In this case, you’ll have to remove your app’s cache to resolve your issue. Should you decide to remove a profile, back up the data files first. All offline cached content will be deleted when you choose Remove. For more information, see Introduction to Outlook Data Files (.pst and .ost). If your issue with Outlook persists, use the repair tool’s "Online Repair" option to fix your app problems. This option takes longer than the first one and requires an active internet connection to resolve your app issues.

Start Outlook in safe mode to fix "Processing" screenIn Windows 10, choose Start, type Outlook.exe /safe, and press Enter.In Windows 7, choose Start, and in the Search programs and files box, type Outlook /safe, and then press Enter.In Windows 8, on the Apps menu, choose Run, type Outlook /safe, and then choose OK.

A well-running Outlook will ensure that you enjoy the full benefits of this popular email program. If you follow the above solutions, your Outlook will perform according to your expectations. If you are trapped in a similar situation that my Outlook is not opening, you may feel disturbed about the problem. In the following post, you will find out solutions for the common Outlook not opening problems bonus tips to prevent the problem from happening again.

Are you having trouble starting Outlook or receiving "Cannot start Microsoft Outlook. Cannot open the Outlook window" error messages? We can fix the problem for you, or you can use the troubleshooting steps we're providing below to help resolve these startup issues. Here's the deal, when Outlook manages to open, all the files you delete will automatically be recreated. It gets better because you also resolve all the Outlook Fix resource center Outlook opening issues. If the in-box Program cannot fix the corrupted Outlook PST files, you can also try Wondershare Repairit for Email.

For more information about when builds are available for their respective channels, go to Update history for Microsoft 365. We're investigating the issue and will update this page when a fix is available. If you're using Outlook 2010, Outlook 2013 or Outlook 2016, uninstall and re-install iCloud to resolve this issue. This issue affects Outlook 2007, Outlook 2010, Outlook 2013, and Outlook 2016. After installing the September Public Update, Outlook 2007 displays mixed languages in the user interface. Follow along with the video below to see how to install our site as a web app on your Outlook Fix resource center home screen.

The built-in Outlook Fix resource center back-off mechanisms in the indexing component of Windows Search or WDS pauses the indexing of Outlook data when the system is under heavy use. The easiest way to let the indexing finish is to leave Outlook running overnight.Additionally, you can reduce performance issues by running Outlook in Cached Exchange Mode. In this mode, Windows Search or WDS searches the local copy of the mailbox instead of the mailbox content on the server. I even reduced mailboxes sizes and that didn't help, I setup a new user (albeit existing PC but new windows profile), and he is having the same issues. If the mailboxes open automatically after removing them and restarting Outlook, they may be auto mapped. This setting can be changed by an Exchange admin by submitting a request via Jira and including the usernames of the client and the usernames of the mailboxes that need to be removed.

Currently, you can't use Outlook on Windows to edit calendars that are shared with your Outlook.com account, even if you've reconnected your Outlook.com account to Outlook. We're working to make it possible to edit shared calendars in Outlook 2016 for Windows. After installing the September Public Update, Outlook 2007 displays mixed languages in the user interface. Ensure that your Outlook recycle bin is empty and then run the Compact Now command to complete the mailbox housekeeping exercise. This, along with all other features, is conveniently available across all platforms for efficient inbox management on any device.

In some scenarios, doing so fixes the "Outlook will not open" issue. However, if installing updates doesn’t fix the problem, then try to repair your Office programs. Then, you can try to start Outlook 2016 in Safe Mode and then check which add-in is causing Outlook issues, disabling that add-in.

Recovery Toolbox worked very well and relatively quickly. The original .ost file must be converted to a pst file using Recovery Toolbox for Outlook and then opened in Outlook. Conversion from OST to PST using Recovery Toolbox for Outlook doesn't require the availability of Exchange Server or Windows Domain Controller. The full version of Recovery Toolbox for Outlook transforms it from a data loss diagnostic tool into a complete data recovery solution.

If it’s an RDS server and the cache is also on the server, if the server crashes, reboots abruptly, is full, there are many reasons. Instead of removing the profile, remove the OST file and let it recreate. Compatibility mode is suitable for older software with Windows 10 that fail to run normally.