New
#1
Really stepping on thin ice here. If I'm off base just ignore me.
May I ask why you want to remove the extension. Is the association wrong or is it that you don't want user to be able to see these files or are you trying to prevent these files from being executed on this machine. The reason may yield a better answer.
Quickly searching google the association don't seem right to me. If I understand, a .nbf file extension can be among other things, a Nokia Backup file, an NTI Backup Now file or an Nvida Scene graphic. So Adobe and Word would not yeild much.
If you want to Restore Default File Extension Type Associations in Windows 10 then Brink has documented the following which may help.
https://www.tenforums.com/tutorials/...dows-10-a.html