Windows Vista Complete PC Backup and large file support

vista_wallpaper Chris Muench shot me an email a week or so ago and asked me if I had run into a Complete PC backup issue with the following obscure error message “A semaphore has expired”.  He had tried several hard drives as the target and it always seemed to fail at the same point close to the end of the backup.  He indicated to me that he was backing up about 65GB of data.  This certainly wasn’t an unusual amount of data.

As it turns out, the reason he hit the error message and it failed is because he was trying to backup a file larger than 4GB.  I always wonder why the error message just can’t say that.  You know something like, “I’m sorry, we cannot backup files larger than 4GB.”

Comments (5)

  1. vaibhavbagaria says:

    FAT32 file system has 4 gb file limitation. Format the disk to NTFS.

  2. Alex Miloev says:


    I do full backup on machine with many files larger than 4 GB – you know, VHDs. Tested restore just once, but it worked just fine.

  3. Keith Combs says:

    Hmmmm….well I guess in Chris’s case the big fat files weren’t appreciated.

  4. Jordan says:

    I too have been able to back up files larger than 4GB when using CPCB. However, when trying to make a backup WIM file of my work computer, IT would fail on trying to capture the larger than 4GB VHD files.

  5. Keith Combs says:

    One last point on this, I re-read the email message from Chris.  The file he had a problem with was 29GB.  That’s a pretty big file.

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