see the FAQs on folders for MP3tag settings:
/t/964/1
If you have a folder %appdata% (type this word into the address bar of the Windows Explorer and press enter) then check if you fine a folder MP3tag.
It could be that you do not have sufficient access rights. Usually that folder is hidden.
Or you have installed MP3tag in a program folder before you switched to W10 but you do not own that folder or have no write permissions for that folder.
Or you use MP3tag with a different user id than the one with which you installed it.
Take ownership of all the folders that relate to MP3tag somehow.