ntbackup "insufficient disk space"

[TechSupp]

Just checked my schools backup and found that they have started to fail with an "insufficient space" error. I am using an external USB drive to back up to and there is enough free disk space as far as I can see. The disk is formatted to NTFS so there is no file limit. Have googled it and have seen some others getting the error but no real solutions as far as I can see. One report did comment on NTbackup setting two copies tp backup when the backup is started (which would cause an out of space error) but don't understand that comment or what two copies they are reffering to?

Anyone got any ideas?

[laserblazer]

Try running scandisk on the backup drive. It might be a reporting error.