OK, this is a long running one, so get your thinking caps on! This fault has reoccurred for countless months, I have tried everything Acronis support had to suggest, thought it had gone a away, and now it turns out it hasn't gone. I really haven't the heart to pursue Acronis any further over a fault they seem unable to fix. Here goes: Once a week, ATI v11 is scheduled to run (at an idle time) a 'My Computer' (all partitions) differential backup of my PC, to my external USB Hard Drive (Seagate), followed by verification. Usually, having backed up OK, the verification fails with the message: "E0007003: Failed to read data from the disk: A possible reason might be bad sectors on the disk" Often there's an accompanying message re 'Insufficient system resources exist to complete the requested service'. I get up most Saturday mornings to find the failed verification message. Without rebooting or changing anything, I then manually verify the backup, and Acronis always says that the backup is fine. This suggests it is a bug. In the course of many months support from Acronis, I have tried: Uninstalling ATI completely and reinstalling the latest version Deleting the 'base' full backup which the differentials build on, and starting again. Deleting unwanted files so my PC's hard drive (250Gb) is less than half full. Reformatting the external hard drive (NTFS). Checking both PC and external hard drive for errors using the most thorough Windows options, and chkdsk /r, and manufacturer-specific disk utilities which check both disks for endless hours, but find no fault ever. Connected the external HDD to a different, non-shared USB port Replaced the USB lead with a high-spec Belkin one. Ran memory checking utilities for hours which confirm my 3Gb or RAM to be fault-free Downloaded the latest Snap.api drivers provided by Acronis Reduced the HDD writing speed by half, in case that was the cause There's probably other things too I've tried, which escape me. The important point is that my Dell PC works fine, has plenty of free 'resources' no fault has ever been found on internal or backup HDD, and that as a manual verification always succeeds, it would suggest that the error is a 'bug'. Googling this problem yields post on this forum back with ATI v9, but don't shed any light. If I backup my laptop to the same Seagate HDD using ATI v11, this always works fine. I have other copies of ATI v11 running similar nightly backups at work, and these always succeed. So I can't say it's ATI v11 at fault specifically. Trouble is, nothing seems to be at fault. I have a healthy Dell PC with plenty of free HDD space and RAM, fully up-to-date with Windows patches etc, scanned regularly for Viruses etc. It just won't verify a scheduled backup with even 50% success rate as an automatic option, but always succeeds to manually verify afterwards. I'd really appreciate anything I or Acronis Support could have overlooked here.