What is mb-clean.exe?

mb-clean.exe (aka Malwarebytes Cleanup Utility) is a tool developed by Malwarebytes to assist in fully removing the following products:
All versions of Malwarebytes 3.x
All versions of Malwarebytes Anti-Malware 2.x
All versions of Malwarebytes Anti-Malware 1.x
All versions of Malwarebytes Anti-Exploit 1.x

Note: mb-clean.exe will eventually replace the legacy version of "mbam-clean.exe".

When to use mb-clean.exe?
If you are having trouble uninstalling any of the supported products mentioned above
If you are having trouble upgrading to a newer version
If you are getting access denied or failed to delete errors during removal
If real-time protection is having trouble starting

What operating systems can I use mb-clean.exe on?
Windows 10 (32/64-bit)
Windows 8.1 (32/64-bit)
Windows 8 (32/64-bit)
Windows 7 (32/64-bit)
Windows Vista (Service Pack 1 or later, 32/64-bit)
Windows XP (Service Pack 3 or later, 32-bit only)