[BetterRed]

Kovid, I appreciate they are not the default associations, but I'm referring to entries such this: HKEY_USERS\S-1-5-21-3755760686-4144392507-2264908130-1000\SOFTWARE\Classes\calibre.AssocFile.DOCM - of which there are about 150.

They effect what's displayed in the Windows 10 File Explorer Open With offer list, if they are not removed when the program is uninstalled they still appear in that list with reference to .exe.s that no longer exist. I don't recall this happening on Windows 7, but it does happen on Windows 10.

Why do I sometimes install 32bit calibre - mainly to support people in my local community who use calibre - at least a dozen of them. Many have poor English skills, others are intimated by forums such as this -- or both. Occasionally I copy their configuration folders and libraries onto one of my machines and then use the 32bit edition of the version of calibre they are using to resolve their problems -- without disturbing my setup. I also do similar for a couple of people who do frequent this forum.

I assume MS still recommends that the registry entries created by an Install be removed when the corresponding Uninstall is executed. If MS don't provide the wherewithal to do that then perhaps the Install should offer the user the possibility of not creating the entries in the first place.

I normally don't worry much about entries not being removed from the registry when something is uninstalled, but in this instance their continued presence impacts on one of the basic features of Windows - File Explorer->Open With. Well, it's basic for those of us who start with the data and use Open With to select the required program.

BR