Backup on W10 skips file

Windows backup always skips 2 files : G:\username\MUSIC and says that it is already on the target drive. This after even reformatting that drive! (on windows 10). Also, a second error involving the file E:\username\MUSIC appears simultaneously, with the statement that the drive E is not available (because I changed the hardware configuration earlier). The error message says, "the backup did not complete successfully" with option to view skipped files. I can't get rid of either file even by reformatting my 2TB backup drive! Anyone have a similar problem?

Could this be related to a missetup of the EFI partitions? If so, can I reinitialize them and how?

When I view the skipped files, I read
Backup skipped backing up G:\MILTONJ\Music as it is on the backup target.
Windows Backup skipped E:\MILTONJ\Music because it is on drive E:\, which is not a supported drive type.

(E:\ is now a 16GB thumb drive)
And these two paths do not exist on my C:\ drive that I'm backing up!


PS: I recently used the free upgrade from Win 8.1 to Win 10.