I’ve got a 256MB USB 2.0 flash drive. Useful doohickey. I’ve been using it a couple times a week since Christmas with no troubles. Until today.
Today, I copied a bunch of files from the flash drive to my home PC. While copying one large ZIP file - the last file of the bunch, as it happens, I got a message box saying “Cannot copy (name-of-your-oh-so-important-file): Data error (cyclic redundancy check).” Trying to decompress the zip file directly from the flash drive caused WinZip to display a similar message: "I/O error - unable to read from zip file."
Fortunately, WinZip offers the option to skip the bad parts of the ZIP and extract the rest of the contents. So I’ve only lost one of the files inside the ZIP.
But can I trust this drive in the future? Is it dying, completely trashed, or fixable with a reformat?
I did some Googling, but I wasn’t able to find anything conclusive. Most of the mentions of this error that I’ve seen were in relation to other media, and lacked definitive fixes or answers. I know that a few bad bits in a flash part - which is exactly how flash parts die - could cause a CRC error. But I know that a hiccup during the write process could do that too.
Details that probably don’t matter: Flash drive is an “AVB” brand. Home PC uses Windows 2000, with a Heisei/NEC USB 2.0 PCI card and a Heisei/NEC USB 2.0 front-panel USB hub, which the drive was plugged in to. Work PC (where the files were copied to the drive) uses Windows XP with USB 1.1 controller built-in to the Intel motherboard. No drivers specific to this particular device were ever installed on either machine.
Ir could simply be a bad zip file. Although rarer that it used too be, downloaded zip files were often riddled with errors and had numerous CRC failures. If the thumb drive did not have enough overhead or slack room to hold the entire zip file, something may have happened in the transfer of the file to the thumb drive and it did not get copied correctly. Id suspect zip file flakiness before I blamed
a memory chip.
Thanks for your response, astro. I do have a lamentable degree of experience with corrupt downloaded zip files. Unfortunately, this zip file was not downloaded, I made it with WinZip myself.
Further, although a corrupt zip file would surely cause WinZip to scream bloody murder, Windows should still be able to copy it from place to place, errors and all. Since I couldn’t do that, I’d have to guess that the CRC check that was failing was at some deep murky level, in part of the device driver or file system driver, not in the WinZip program.
I just now formatted the flash drive, and tried filling it up with about a dozen zip files. Then I used the “test” option in a zip decompressor to check the CRC of all of the files; they all passed. Since I don’t know exactly how many bytes I could store on the drive before, I can’t tell if a few “bad sectors” have been secreted away by the format. I’m stuck in head-scratching mode now. I don’t think I’ll be using the flash drive for anything really important for a while. (I guess I’ll have to burn a CD to smuggle those plans for the Death Star…)
I had a similar problem with a USB flash drive just the other day.
Seems that the first rule is to always use the “Stop USB device” option from the system tray before unplugging the device. That fixed some of my files. If I didn’t do that, all files would end up corrupted.
Then I tried writing a .rar file onto the drive. It gave a bad CRC error every time, no matter what I tried. It was a 128MB drive and the .rar file was 100MB. First, I thought that maybe it had to do with the .rar headers, so I zipped the .rar into .zip. The .zip copied properly, but on trying to unrar the .rar I got the CRC error again. Then I tried chopping the .rar into 20MB parts, thinking maybe 100MB was creating the problem. The first two parts copied properly, but the third gave the CRC error again. Then I tried renaming the .rar to some random extension and that worked on one file, but not for the rest of the parts. All very random.
So I just gave up and uploaded the file and wrote it on a CD from elsewhere.