I dug this up from a 10 year old course material I wrote but it’s still very usable
One weird thing in Windows OS troubleshooting is that Microsoft wants software developers to use MSI as the installation method and at the same time says on their documentation that if you run into problems after installing some software you should boot into Safe Mode and uninstall it. The weird part is the fact that Safe Mode in Windows actually doesn’t allow the Windows Installer service to start thus preventing uninstallation of any software that was installed with an MSI!
You can get around this by tweaking the Safe Mode registry key with following command:
REG ADD "HKEY_LOCAL_MACHINE\CurrentControlSet\Control\SafeBoot\Minimal\MSIServer" /VE /T REG_SZ /D "Service"
After this you can start the service with the following command or do it graphically with Services.msc:
NET START msiserver
Now you can uninstall any software that was installed by an MSI!