I have encountered repeated problems with both TI 10 & 11 (trial) when backing up to external USB HDs, on a number of different PCs. At about 60% of a large backup, I get: Failed to backup file or folder 'C:\Users\conor\Videos'. Error writing the file. (0x40003) function = "WriteFileNoCache" Tag = 0x7CEB2CDC9FB12189 The request could not be performed because of an I/O device error (0xFFF0) code = 8007045D) Tag = 0xBD28FDBD64EDB8AF: Retry/Ignore/Cancel This has happened on both XP and Vista PCs, using 2 different USB hard drives. There is no problem if backing up to a local HD. I have also experienced this error backing up across a wireless network, which I attributed to a dropped connection, but an external HD? I have attempted splitting the Archives into 700Mb segments, but it made no difference. This is driving me mad - if it wasn't for Retrospect, I wouldn't have any successful backups. Still, I like the feel of TrueImage, and would dearly like to get it working. Any ideas?