Open in Safe Mode and Disable Add-ins In many cases, this error occurs due to conflicts with Outlook Add-ins.
Reset Navigation Pane Corruption of the Navigation Pane’s XML file is also another reason for Microsoft Outlook failing to start.
Repair PST Data File
Delete OST Data File
Create New Profile
Check Compatibility Mode
Perform Clean Boot
Repair / Reinstall Office
How to fix cannot start Microsoft Outlook error?
Quick Solutions to Fix Microsoft Outlook Can’t Start Error: Close Outlook
Press “Win + R” when you want to open the “Run” dialog box.
Type Outlook /safe (note the space), then click OK.
In the Select Profiles dialog, select the default settings and simply click OK.
Now, to disable add-ons, click Theme -> File Options -> Add-ons.
Under Discover and manage Office Add-ins, make sure the COM add-ins check box is checked, and then click OK.
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How do I fix outlook not opening?
To prevent your Outlook from opening, pay attention to the following measures: Starting the process. Outlook often leaves certain processes running in the background.
Set up an email account. If this is your first time using Outlook, you need to change your account email address correctly.
installation error.
Disable virus protection.
Do not interrupt Outlook during AutoArchive.
How to deal with ‘Microsoft Outlook not responding’ error?
Use the specific Windows R+ key combination to open the Run command.
Type keep with and press Enter to start Outlook in safe mode: outlook.exe /safe
For now, click OK.
Close Outlook (safe application mode).
Why is outlook unable to open?
Outlook definitely won’t open and shows a fatal error code. Reset the navigation bar using the outlook.exe /resetnavpane command. The search navigation box is usually located on the left edge of the application window.
Safely identify fake add-ons in mode. If this quick fix works, the following suspected culprits are not add-ins that are built into Outlook.
Repair this corrupted Outlook profile.
How do you fix error Cannot start Microsoft Office Outlook Cannot open the Outlook window?
Check if Outlook corrupts the Outlook.exe mode. Find image compatibility on your computer. Right-click the Outlook.exe file, select Properties, then select Compatibility from the tab. If any of your current fields in the Compatibility tab are definitely checked, uncheck the box and choose Apply > OK. Restart Outlook.
How do you fix Cannot start Microsoft Outlook Cannot open the Outlook window the set of folders Cannot be opened an unexpected error has occurred?
If Outlook still says “Microsoft cannot start Outlook. The Outlook window cannot be opened. Unable to open version set”, you can just try to manually delete the navigation bar configuration file and leave Outlook to reset it. Press the Windows + R keys on your keyboard to open the Run application.

Vijay is a tech writer with years of experience in the Windows world. He’s seen it all – from simple problems to catastrophic system failures. He loves nothing more than helping people fix their PCs, and he’s always happy to share his wisdom with anyone who needs it.
When Vijay isn’t fixing Windows problems, he likes to spend time with his wife and two young children. He also enjoys reading, playing cricket, and watching Bollywood movies.