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I've got a 1tb drive in my machine that holds everything - yes, my data needs are modest - and a 2.5tb external USB drive that I'd like to use for backup. My big problem is that Windows won't successfully back up to the 2.5tb drive. It gets near the end, and then stops and declares failure with a completely useless error code.

I have, very occasionally, found references to greater-than-2tb backup drives (not partitions) being a problem with Windows 7's backup utilities. (This may have been after Googling the error code; I'm not going to wait three hours for another backup failure just to find out.)

I'd like to get this to work automatically. It doesn't have to be Windows 7's backup utility doing the backups, but it would be nice.

(If it matters, the primary hard drive is encrypted with TrueCrypt. The external drive isn't encrypted yet, but it will be.)

(My apologies if this is a duplicate. Nobody else seems to have covered the specific 2tb-backup-drive-target issue. It's hard to even find a link on the 'Net.)

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What is the error code? – Darth Android Jan 3 '12 at 15:08
@Darth: I will have to dig it up later. – jprete Jan 3 '12 at 18:08

If you selected the "system image" option, then the problem your are encountering is due to the 2040GB size limitation of VHD files. Source:

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Just to be clear, the system drive is 1tb, and the drive holding the backup is 2.5tb. Is this still an issue? If so, then I will try it without a system image (which would also greatly decrease what needs a backup). – jprete Jan 3 '12 at 18:12
Ah, I see. It should be able to backup a 1TB drive just fine. Are either of the drives advanced format drives (4096-byte sectors)? – cmorse Jan 3 '12 at 18:27

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