Backup disappears immediately so cannot be validated
I tried to perform a regular backup but forgot to plug in the disk I use for backups. Having realised the error, I plugged the disk in and tried the backup again. This proceeded normally, but when the time came to validate the backup, it was unable to open the file. When I checked with Windows Explorer, it did not exist!
I tried the backup again. While it was proceeding, I checked that the .tib file it was writing to did exist. After completing the backup, it again couldn't find the file to validate it. I checked with Windows Explorer again, which showed it did not exist.
How can I get out of this cycle?
(Using Windows 7 and True Image Home 2012)