hello,
Causes-
You have not installed the latest updates.
Outlook is in use by another process.
Outlook is loading external content, such as images in an email message.
A previously installed add-in is interfering with Outlook.
Your mailboxes are too large.
Your AppData folder is redirected to a network location.
You have to repair your Office programs.
Outlook data files have become corrupted or damaged.
Your installed antivirus software is outdated, or it conflicts with Outlook.
Your user profile has become corrupted.
Another program conflicts with Outlook.
Resolve-
1. Go to the Control Panel (Start>Settings>Control Panel)
2. Select Add or Remove Programs.
3. Choose Microsoft Office/Outlook.
4. Click the Change button.
5. Select the Reinstall or Repair button, click Next.
6. Choose Detect and Repair.
7. Click Install and follow any prompts provided by the repair tool.
Thank you.