Yes I seached but got no answer. I am a new user (Ver. 10.0) who has just done a first full backup successfully and a first scheduled differential backup - unsuccessfully (it seems) to a 250GB external USB 2.0 hard drive. The backup was scheduled when my computer (XP Home) was in sleep mode (manually activated). The log said the backup was completed but with errors and one warning. It appears the computer was taken out of sleep mode ?? but when I went to the computer it was still in sleep mode - no auto sleep mode set. I cannot find a list of error code meanings. Could the errors possibly be due to sleep mode? If not how do I determine if the backup was successful and what the errors mean? Does TrueImage work in the background during sleep mode?