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  1. #1
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    Windows 7 64-bit fails copying very large files in Windows Explorer

    I have a very interesting problem: One user can't copy a very large file (~750MB) from one mapped drive to another mapped drive using Windows Explorer. Here's the specifics:

    - Other users can copy this file just fine using Windows Explorer.
    - If she logs into another machine, she too can copy this file.
    - She can copy this file down to a local drive or a flash drive, and then copy the file up to the other mapped drive, using Windows Explorer.
    - She can copy the file directly from one mapped drive to the other via the Command Window (DOS).
    - Her machine is Windows7 64-bit. The machines that work are either 32-bit Windows 7 or Windows XP.
    - Both mapped drives are on the same Windows 2008 R2 server and volume.
    - If I log onto the server itself and copy the file, it works fine (and is very fast).

    It appears that Windows will start copying the file, but the first time it goes to calculate the Estimated Time, it just fails.

    All this points to some problem with Windows 7 64-bit copying large files in Windows Explorer. It's a hard problem to Google the solution for, so I hope someone here can point me in the right direction. Alternatives to Windows Explorer probably aren't the ideal solution.

    Thanks in Advance!

  2. #2
    5 Star Lounger
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  3. #3
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    I think it could be an issue with TCP auto-tuning which has been around for at least five years: Fix for Mapped Drive gets disconnected while copying large files in Windows 7 and Vista

    Perhaps the combination of Windows 7 TCP auto-tuning and the 64-bit OS causes packets to be sent too quickly for some intermediate network component to keep pace with (because it doesn't do TCP Window Scaling)?

    Bruce

  4. #4
    New Lounger
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    Fixed

    Thanks Bruce and Zig. I tried Bruce's solution first since it didn't involve a new program and that worked. I suspected it was something like that, thanks! Zip, TeraCopy looks great too and I definitely would have used that as my next solution.

    Eric

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