Ask Leo!: Disks and Mass Storage

My flash drive suddenly stopped working, how do I recover the data on it?

leo@pugetsoundsoftware (Leo A. Notenboom) — Thu, 19 Nov 2009 13:09:26 -08:00

I have a flash disk which has been working well for quite some time. Just yesterday it refused to work. It was recognized by the computer but when I tried opening it I got the message that the disk needs formatting. I tried using it on another computer but the same message appeared. I also tried autoplay but nothing happened. When I opened the properties of the disk the file system was indicated as RAW. The data in it is very important and I need to recover it. Please advise.

]]> I really have no answer for you. I honestly believe that your data is gone.

However before you leave and potentially repeat the mistakes of the past I'd encourage you to keep reading.

For anyone who uses a USB flash drive, there are two extremely important lessons to learn here.

One of which actually applies to everyone - flash drive user or not.

While do file timestamps compare differently every time change?

leo@pugetsoundsoftware (Leo A. Notenboom) — Wed, 18 Nov 2009 14:13:42 -08:00

Every time change (now daylight to standard), the timestamps on all files on my 3 hard disks (1 local, 2 networked) show the new time (i.e., 1 hour less in the Fall) BUT those same files on my removable disk (Cruzer 8GB thumb drive) still have the "old" time (i.e., 1 hour more in the Fall). This causes the entire set of files to miscompare when compared based on time (and I have to recopy all files (GBs) to the removable disk. Been happening for years and have never seen an explanation.

]]> Years ago, one of the ways I took work home was to use an external disk and a file copying tool that copied only files that had changed, using the time stamps to determine which files should be copied.

Once a year everything changed and all files were copied, and once a year a bunch of files would be copied in wrong direction.

And, like you, it happened every time we left and entered daylight saving time.

Why is my "generic volume in use" when removing my external hard drive?

leo@pugetsoundsoftware (Leo A. Notenboom) — Thu, 15 Oct 2009 08:00:00 -08:00

I bought a new 1TB external hard drive the other day and installed it on my laptop right away, everything was working fine until I tried to safely remove it. Whenever I click safely remove it says "Windows cant stop your generic volume device because it is in use". I checked everything and I didn't have a single program running. I don't want to shut it off manually because I have hundreds of important files on it and I don't want to lose them. can you help?

]]> Oh, just because you don't have a program running, doesn't mean that there aren't other programs running. Heck, that's all Windows itself is: a computer program.

What we have is a situation very much like How can I find out who is using a "file in use"? - except that we don't know the name of the file, or whatever else might be "in use".

I'll show you my technique, which looks very similar to the file in use scenario, as well as cover an easily overlooked common cause or two.

Can I repartition my hard disk to remove CRC errors?

leo@pugetsoundsoftware (Leo A. Notenboom) — Sat, 19 Sep 2009 14:01:13 -08:00

I've got a 500 GB slave HD which was partitioned 2 partitions and a 160GB HD as a master HD. I use Utorrent as a torrents client. Weeks ago I started getting this error message by utorrent: "Error: data error ( cyclic redundancy check )" when downloading to my slave HD ( my master HD works fine). Chkdsk started to report bad sectors so I've deleted the partition with partition magic and created it again and bad sectors were gone. But this error keeps coming back; I even partitioned it to 6 partitions but no use. The system file is ntfs.

]]> Unfortunately, while changing the partitioning on your hard drive can make it seem like a bad sector has disappeared, it hasn't. All it has done is rearranged things so that if you don't run across the error soon, you'll almost certainly run across it later.

Put more bluntly: repartitioning will not fix bad sectors.

What does "Cannot copy - the request could not be performed because of an I/O device error" mean, and what do I do?

leo@pugetsoundsoftware (Leo A. Notenboom) — Sun, 16 Aug 2009 08:00:00 -08:00

I tried to copy a file to my flash memory, while I was copying this error message appeared "Cannot copy (file name): the request could not be performed because of an I/O device error" and I don't know why?

]]> Well, it's hard to say exactly why it happened, though of course I have theories.

The real question is what to do next. In the case of a flash drive, the answer's fairly clear. In the case of other types of media, there additional options.