Looking at the image you put up in post #3, the flashdrive shows as "unformatted" in Disk Utility. This suggests damage to the partition map or other "non-data" sectors of the drive.
If you have no luck trying to recover or repair the flashdrive "as is", I would suggest you do this:
- Get ahold of one of the Mac data recovery apps, such as
Data Rescue 3
Disk Drill
Stellar Phoenix Data Recovery
Nice To Recover
- As a very first attempt to recover, see if any of the above can repair the flashdrive's directory. If that doesn't work, you'll have to go to the next steps.
- Re-initialize the flashdrive to HFS+ using Disk Utility (YES, you ARE reading that correctly)
- DO NOT put any new files on the newly-reinitialized flashdrive. Instead, launch your file recovery app, and now attempt to recover the files on the drive.
- If the data recovery app "sees something", let it scavenge the flashdrive for whatever files it finds. Then, recover the files to a DIFFERENT location (such as your internal hard drive). You will lose folder hierarchies and you may lose some file names as well. That's the way data recovery works.
Why I suggested this:
A drive's directory/partition map can get corrupted, leaving the drive "unreadable" from the user's perspective. But just because the directory has gone bad, DOES NOT mean that the data is "damaged". It may still be there, untouched. But since the directory serves as the "table of contents" and/or "index" to the data, you can't see it or access it.
By re-intializing the drive, you are replacing the corrupted and unreadable directory with a "clean" one. You can now mount the drive on the desktop. However, because the you have re-initialized the drive, you have wiped clean the contents of the DIRECTORY (emphasis intentional) and have replaced it with a new, but "empty" one. However, just re-initializing the drive DOES NOT "wipe" the data sectors. They are left alone until new data is actually written to the drive, then the directory is updated to reflect this action.
What this means is that even though the drives "shows as if it were empty" because you replaced the directory, the old data may still be there. And if it is, a data recovery app like DataRescue3 can go in (bypassing the directory), and "scavenge" the sectors of the drive. It will find and re-assemble the "missing" files.
Again, because things like file names and folder hierarchies are "structures of the directory", you will almost certainly lose most of this information. But, the DATA part of the files may be recoverable -- and that's what's important, right?