I don't think that is the case. According to the article you linked, that would apply if:

Your computer has more than one operating system installed...
or
Your computer is set up to run BitLocker Drive Encryption.

Neither is the case with my computer. The F:> and the L:> drives are strictly data drives, both of them WD20EARS 2-TB drives. The only differences I can see in their setup is that one of them shows a status of "System, Active" and the other does not, and the "System, Active" drive has 29 GB less free space. Well, 31GB now, after clearing the recycle bins.

Except for the extra files caused by/created for the "System, Active" status the two drives are byte for byte identical, but several of those files don't get backed up to the L:> drive because of "...file in use.." error. These differences only account for about 55 kilobytes, however, so... perhaps you are right after all, because something is eating up those 31 missing gigabytes.

How would I find a hidden partition?

tanstaafl.

Edit: Possibly this? ? Then I would reformat the drive and copy just the files I want from the backup?

db