You will need a master password to your FM3 file. Try logging into a copy of the file in FM3 prior to conversion. Go into the Define Passwords dialog (if you don't see it, you aren't using a master password.) Try changing or deleting the passwords, then try converting the file again. Remember, the password will be case sensitive once it's converted.
Once you can login successfully into the converted file, see if you can edit your accounts in the Accounts & Privileges dialog.
Confirmed this is the only password they know for the file, it doesn't have rights to the Access Priviledges section. The data is fully viewable in FM3 but when it gets upgraded it isn't. I guess I will have to try and get the admin password for FM3 unless there are other ideas.
Finding the admin password has helped. The access rights for the only account they did have did not map properly when migrated, it left the account with "custom priviledges" in the file. Before it was migrated the account had everything except override data entry warnings checked but apparently that doesn't map well in the migration. Quick changes with the admin account and I'm back in business. Only 50000 more pw protected files to go