Many compressed downloads have CRC errors

Discussion in 'Windows Desktop Systems' started by ECO, Aug 27, 2002.

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  1. ECO

    ECO Guest

    Most of the time I download compressed files I received CRC errors. What software is out there that can check if my hard drives have gone bad? Also, could there be any other factors, besides bad hard drives?
     
  2. gonaads

    gonaads Beware the G-Man Political User Folding Team

    It can also be bad downloads.


    Also:

    About CRC Errors
    A CRC error indicates that some data in your Zip file is damaged. CRC stands for “cyclic redundancy check”. It is a calculation made from all the data in a file to insure accuracy in transmission. When you add a file to a Zip file, WinZip calculates a CRC value for the file and saves the value in the Zip file. When you later extract the file from the Zip file, WinZip® calculates the CRC of the extracted file and compares it to the value stored when the file was zipped. If these two CRC values do not match, the file that was extracted does not match the original file, and WinZip will display a “CRC Error” message.

    When the data in a Zip file is damaged, it may not be possible to extract all of the files from the Zip file correctly. Damaged data can affect the entire Zip file, multiple files, or just one file.

    Why CRC Errors Occur
    There are many possible causes for data damage. Among the most common is telephone line noise or some other transfer error when downloading a Zip file from an online source such as the Internet, AOL, or CompuServe. Such an error can introduce invalid data into a Zip file. Some other possible causes include exposure of disks to excessive temperatures or magnetic fields, cross-linked disk sectors, and mechanical problems with disk drives.

    What to do if a CRC Error Occurs
    The best solution to the problem of a damaged Zip file is to try to obtain another copy of the file. For example, use your backup copy of the file or get a new copy from the original source. If you obtained the Zip file by downloading it, then downloading it again will almost always solve the problem.

    CRC Errors on Removable disks
    If the damaged Zip file is on a removable disk, the removable disk may be physically damaged, or the data on it may have been corrupted. In these cases, the only completely reliable solution is to use another copy of the disk or Zip file that is undamaged. There are, however, two other situations in which it may be possible to recover some files from a removable disk.

    · The removable disk drive that you are using to unzip the Zip file may be malfunctioning. Try using a different disk drive, if possible.
    · If the removable disk drive you are using to unzip the Zip file is not the same drive that was used to store the Zip file on the removable disk, and you have access to the original drive, try using this drive to unzip. It is possible that the original drive may be able to read the disk; if so, you can extract your files using this disk drive (and have your removable disk drives checked out--at least one of them may be out of alignment). Otherwise, the removable disk itself or the data on it is probably damaged.

    A “Last Resort” for CRC Errors

    If you cannot download a new copy of the Zip file, obtain a replacement disk, or use a backup copy, you may still be able to recover some of your files, and even save portions of the files that are damaged in the Zip file. Here is the recommended procedure.

    1. Start WinZip, switch to the Classic interface, and open the damaged Zip file.
    2. Select Extract from WinZip's Actions menu, or click the Extract button on the WinZip toolbar.
    3. In the Extract dialog, check the All Files option button and select the folder into which you want to extract files. Then click OK.
    4. WinZip will extract any undamaged files to the selected folder; for any damaged files, WinZip will display a CRC Error message. For each such file, before clicking OK in the error message window, use Windows Explorer to open the extract folder and look for the file; some portion of it will probably already have been extracted. Copy the partial file to another folder and then click OK in the WinZip error message window. This will erase the partially extracted file from the extract folder, leaving intact the copy of the file you made in the other folder.

    Whether or not a damaged file partially recovered using this procedure will be useful depends on the nature of the file, what kind of damage there is, how much of the file was recovered successfully, and what kind of program(s) use the file. In some cases, a partial file is of no use at all; in some cases, loading a partial file into your application program and re-saving it will completely restore the data. In other (perhaps most) cases, the result will lie somewhere between these two extremes--some of the data will be recovered, and some will be lost.

    Copyright © 1991-2000 by WinZip Computing, Inc. All rights reserved.
     
  3. Timeo27

    Timeo27 Guest

    What types of files are you downloading, ECO? Zip? Rar? Sometimes when you open a rar file with winzip or winace, or other things that mix up file types and primary programs you can get crc errors.

    For example, for the longest time I was getting all these crc errors with rar files when I was trying to open them with winace, then I realized that you have to open most of those newer rars with winrar.
     
  4. ECO

    ECO Guest

    That's not the problem. I have the newest version of both WinRAR and WinACE.
     
  5. gonaads

    gonaads Beware the G-Man Political User Folding Team

    What type of dial up do you have?

    Again, it could be telephone line noise or some other transfer error.

    But it you think it's a HD problem, go to the Manufactureres (of the HD) web site and search for a HD testing utility.
     
  6. ECO

    ECO Guest

    I don't have dialup, I have Bell Sympatico HSE (ADSL).
     
  7. DopeWeasel

    DopeWeasel OSNN One Post Wonder

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    I have the same problem. I've figured out that it's almost definatly a problem with winRAR but I can't pinpoint it or figure out how to correct it. Other things that I've noticed are that I can test a file in winRAR and it will test fine, check the SFV file with FlashSFV and it tests fine, but when I extract I still get crc errors. I've been able to take files that won't extract on this computer and extract them with no errors on another. I've also only noticed this problem in RAR files that are spanned (rar, r00, r01 et cetera) accross multiple rars, never from a single compressed file... the bigger the combined archive, the more likely it is to happen.

    I'm using the latest verson of winRAR 3.40b4. I've tried several different versions (uninstalling and then installing the other version) to no avail. I've also tried to use IZArc to extract, sometimes it works but usually not.

    Sombody please help so I can confidently use this program again.
     
  8. DopeWeasel

    DopeWeasel OSNN One Post Wonder

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    Oh, also...

    CRC error displays at random points in the archive... If I for example extract an archive set to one folder I may get a CRC error only after it has processed the entire volume (outputting only an error like this: "! CRC failed in file.bin. The file is corrupt"), but the same exact archive extracted to a different folder could tell me that there's a CRC error in "! C:\CD3\file.r20: Packed data CRC failed in file.bin. The volume is corrupt"

    Then I'll go back and run my SFV checker and file.r20 reads the crc fine, also I'll run the Test mode in WinRAR and it completes with no errors. But it STILL won't extract.

    I'll admitt... this IS strange but I honestly can't figure it out.

    I really hope sombody here can help, have you seen the winRAR forums? They're almost completly empty. And I've even gone to the extent of reformatting my C drive in order to correct this and other problems. No, even a complete format/reinstall of my drive and windows did NOT fix this problem.
     
  9. DopeWeasel

    DopeWeasel OSNN One Post Wonder

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    I've just been told that some people experiance problems like this with RAID configs. I am using a PCI ad in card for my extra ATA133 drives. It would make sence that it's a hardware problem if I've been through a format/reinstall and still encounter the problems.

    Will test extraction on the different drives and see if that makes a difference.
     
  10. DopeWeasel

    DopeWeasel OSNN One Post Wonder

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    THAT'S IT!!!!!!!!!!!!!!

    I've just extracted one of the problem archives that I couldn't extract because it was on my D: drive. I now know that I have to move everything from D to C in order to extract it.... what a pain huh?

    Well, I guess it works anyway... I hope that this helped the person that started this thread.



    UPDATE: Looks like I spoke too soon here :( I'm still getting the same errors in other files. I feel like I could be close though... any thoughts anyone?
     
  11. DopeWeasel

    DopeWeasel OSNN One Post Wonder

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    Oh, it seems that the copy process somhow creates the crc errors within the files... explination: when I copied the volume from D to C - *.r03, *.r06 and others got crc errors... I then simply replaced *.r03 and the others one at a time from my D drive and YES it got rid of the errors. I checked with FlashSFV and then extracted.

    Update: Been doing some research and found that this person is having the same sort of problems but I can't see that anyone replied to him -- https://secure.experts-exchange.com...re+error&searchType=all&registrationSource=10

    terribly sorry for the long stupid link -- it's on some greedy pay site, just thought a little extra explination might help.
     
  12. dreamliner77

    dreamliner77 The Analog Kid

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    first, i'd make sure that you can move large chunks of data between harddrives and not suffer corruption.
     
  13. DopeWeasel

    DopeWeasel OSNN One Post Wonder

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    Accually, I don't think that I can. The other day while moving a spanned archive I had crc errors in 2 of the files that it moved. I had to recopy the files one at a time in order to aviod corruption.

    Yesterday I also reverified the fact that I can copy files to CD-RW that won't extract on this computer and extract them with no errors on another.

    I really don't know where to turn next... I'm almost certian now that it's a hardware problem, but why? And how would I go about correcting it? If it's because of my IDE controller card just replacing it could put me back in the same place that I started.
     
  14. dreamliner77

    dreamliner77 The Analog Kid

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    1) Run memtest86 to make sure it's not the ram that's corrupting data.
    2) Make sure all harddrives are running UDMA5/6
    3) Reinstall IDE drivers
    4) IF there's still problems, it sounds like it's probably your add in card. Is it a pure ata card, or is it a raid card?
     
  15. cryogenic

    cryogenic OSNN Addict

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    Don't forget it could very well be a bad cable... Try replacing the cable first as that's probably the quickest and simplest way of handling it. I've heard of this problem being more common on cheap rounded cables. They have issues with signalling and end up causing data corruption due to "noise" in the signal. Outside of that, the steps that dreamliner outlined should suffice.
     
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