Follow the below steps to troubleshoot and fix MS Outlook not starting issue.
Several reasons that Outlook may not start including:
⦁ One or more add ins are preventing Outlook from starting
⦁ Profile is corrupted
⦁ Outlook.exe is corrupted
⦁ Errors in Outlook Data Files
Fix above issues as follows:
1) Start Outlook in Safe Mode:
two ways: Right click Start | Run | Outlook.exe /safe
OR hold down Ctrl key while starting Outlook shortcut.
Then navigate to File | Options | Add-Ins
Now you can select Add-Ins to be disabled before attempting to start Outlook normally.
Disable one at a time (and then re-start Outlook) in order to determine which particular Add-In is the issue.
2) If Profile is corrupted, we can create another Profile and see if that will start Outlook.
Control Panel | Mail. If you can’t see mail switch to large icons and it should be there!
Select Show Profiles
Click Add to create a new Profile.
Enter a Name then click OK.
On the Auto Account Setup page for the Add Account Wizard, under E-mail Account fill in your name, email address and password then click Next.
On the Mail page, select to Prompt for a Profile to be used when starting Outlook.
3) If Outlook itself is corrupted try to do an Office Repair as follows:
Control Panel | Programs and Features
Highlight Microsoft Office 20xx or Office 365 then click on Change:
Click Yes on Do you want to allow this App to make changes to your device?
Following screen is displayed:
Quick Repair should already be selected. Click Repair. Process runs for a few minutes.
Then can try to start Outlook again to see if issue is fixed.
4) Errors in Outlook Data File. You can use the Inbox Repair tool SCANPST.EXE to diagnose and repair errors in your Outlook data file.
This may be the issue when you receive a message saying Outlook can’t open your data file or set of folders.
To repair Outlook data file (.pst) file:
Exit Outlook and browse to one of the following file locations using Windows Explorer:
Outlook 2019: C:\Program Files (x86)\Microsoft Office\root\Office16
Outlook 2016: C:\Program Files (x86)\Microsoft Office\root\Office16
Outlook 2013: C:\Program Files (x86)\Microsoft Office\Office15
Outlook 2010: C:\Program Files (x86)\Microsoft Office\Office14 Outlook 2007: C:\Program Files (x86)\Microsoft Office\Office12
Now double click (execute) SCANPST.EXE .
Select browse to select the Outlook Data file you want to scan. Choose Start to begin.
If errors are found select Repair.
Once done, start Outlook using the repaired data file.
Any items recovered by SCANPST is placed in the Lost and Found folder.