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Miscompares, orphans

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  • Miscompares, orphans

    In the process of transferring files from one PC to another, I did a Win Explorer copy of about 50GB (19,000 files) from an XP PC to a Win 7 PC.

    I then purchased BC3 and ran a folder compare between the XP and Win 7 PCs of those files. (BC3 is running on the Win 7 PC).

    The results of the compare were 2 file miscompares.

    File miscompare #1 was a photo. I ran a fc /b (binary compare using Windows' fc command) at a command prompt on this file against the original. Windows reported the file identical. With the original BC3 session still open, I selected that one photo file and reran the compare operation. It too then compared identical. What is up with that?

    File miscompare #2 was a large VMware workstation file. Did the same procedure as with file #1. Got the exact same results. Windows fc /b reports file identical. BC3 reports file identical the second time.

    My first reaction would be a failure somewhere along the transer path (bad RAM, network, storage, etc.) that occurred during the compare but not the original copy or the second compare operation.

    Has anyone seen this before? We transfer a lot of data on our network and we tend to run fc /b on large transfers and have never seen an issue. Any suggestions as to what might be going on with BC3?


  • #2
    I haven't seen this behavior before. My thoughts match yours that it might be a problem with ram, network, or storage but it's hard to know for sure.

    Just to make sure there isn't a cached copy of bad data somewhere, you can try checking "Bypass disk cache during binary comparisons" in the Handling tab of Session > Session Settings. If you already have a session loaded you can use the "Edit Full Refresh" command to run the comparison again.
    Chris K Scooter Software


    • #3
      the same I have

      I go from Seagate 640Gb to Seagate FreeAgent Desk 2Tb. I copy approx 60000 files total 600Gb. Most of them - my photos (jpg+CR2 files).
      Then I compare folders by BC3. First - 2 differences. I compare by content by TotalCommander each file - files are identical! I try again by BC3 - no differences.
      I try many times. And now I am sure - if I compare many files BC3 will say several diffs. But it will be mistake - really this files will be identical.
      Why? What to do?


      • #4

        Does the timestamp correctly refresh without quitting Beyond Compare 3? If you perform a quick Refresh (F5) does it update correctly?

        If not, if you perform a full-refresh (Ctrl+F5), does it update correctly?
        Aaron P Scooter Software


        • #5
          Timestamp work correctly as in Fast Refresh also in Full refresh.
          Usially I do next:
          <Folder compare>, then in left and right windows set path (ex: K:\Foto\ and
          L:\Foto\), then <Edit>,<Select All>, then <=?>(Compare contents).
          Comparing started
          K:\Foto\ = 390 145 391 657 bytes in 57 398 files in 529 dir
          Approx after 7hours (+/- several min) comparing finished
          Window with results open/
          Usially 5-6 files diffs, other ok
          After this, manually by TotalCommander I compare each file (from 5-6) (compare contents). Allways result - files identical! After I do the same by BC3 (each file) the same result - files identical! I do this more than 5 times. And I have several such directories. Every time compare means 3-7 files diffs, every time files are different (diffs in different files), manually - all ok.
          First I think - HDD or RAM or Computer.
          But HDD, and all tests gone ok
          RAM or Computer - but no errors during coping (I copied all files only one time,
          than many times try to compare without diffs).
          As the result - I am not sure that something wrong in my equipment.
          So ?


          • #6
            I noticed this effect several times, i. e.:
            Copying 16k mp3-files from local to external HDD was successful (via USB using FTP or Windows share).
            The comparision I performed later (next day) showed some different files (different time stamp and file size!).
            Refresh selection on the parent folder corrects the result (no different files).
            If the external HDD was connected via WLAN/USB using FTP I had to refresh many times to get the correct result.
            I think that BC sometimes gets wrong file information, perhaps depending on the connection to the external storage.


            • #7
              Thanks for the info.

              If you are ever unsure of the comparison, you can perform one of the refreshes and/or perform a Binary Content comparison.

              For your K:\ and L:\ locations, are the plugged directly into the machine running Beyond Compare, or are they accessed over the network?
              Aaron P Scooter Software