Can't open SQL Server Management Studio 18 - "MRU Package did not load correctly" and "Cannot create the window"

Question

This issue is driving me crazy. I can't open SQL Server Management Studio (SSMS) 18. When I try to open it I get the follow things:

• Starts fine with the small window that says "Microsoft SQL Server Management Studio v18.6"...
• But then I get an error window saying: "The 'MRU Package' package did not load correctly. The problem may have been caused by a configuration change or by the installation of another extension"...
• After that I get another error window saying: "Cannot create the window".

Here's an Imgur link with pictures of the errors: Pictures

And that's it. I've been stucked there.

Things I've already did/tried:

1. Installed SSMS 18
2. Installed SQL Server 2019
3. Uninstalled Visual Studio 2017
4. Installed Visual Studio 2019
5. Re-installed SQL Server 2019
6. Repair installation of SSMS 18
7. Re-installed SSMS 18
8. Installed Visual Shell 2015
9. Rebooted PC several times

I don't know what else to do. I've been struggling with this since yesterday. I've searched for solutions but couldn't find anything that solved the problem.

Hope someone can help me. Thanks in advance.