Home Forums Peripherals & Multimedia Peripherals USB drive won't mount

I've been using a 4GB USB drive to acquire large files (via a PC with broadband access) and then download them to my iMac.
Up to now no problems whatsoever.

Now, when I plug it into my iMac, it won't show up on the Desktop. When I run Disk Utility, it recognizes the media and it allows me to verify and repair the disk and updates the boot support partitions. However, except for a split second at the end of the disk repair, the icon does not show up on the Desktop. And it still won't mount.

Any suggestions as to what's going on and how to fix it?

Another thread talked about using a fresh (quality) USB cable, making sure there is no obvious broadcast interference (e.g., Bluetooth from a trackpad, keyboard) which can be minimized with shielding. Is it a direct plug-in or via a hub? Look to see if the hub is dropping off.

I'm sure in your case when it worked and now stops working it is very perplexing, but I have experienced similar and found that with osMac 11 and 12 USB has become intermittently flakey.

Have you tried shutting down and restarting your iMac?

The item is a thumb drive that I'm plugging into a port on my keyboard (as I have always done).

I haven't tried shutting down and restarting the iMac since Disk Utility recognizes that the drive is there. It just won't mount.

Following is a clutch of log entries associated with the issue (in case there's something there of use in diagnosis):

fseventsd: could not open <</Volumes/PNY-4GB/.fseventsd/fseventsd-uuid>> (No such file or directory)

fseventsd: log dir: /Volumes/PNY-4GB/.fseventsd getting new uuid: 146F95A8-4197-44B5-A8C2-A54FDB94A5AB

fseventsd: Events arrived for /Volumes/PNY-4GB after an unmount request! Re-initializing.

fseventsd: creating a dls for /Volumes/PNY-4GB but it already has one...

diskmanagementd: DM <-T-[DMToolBootPreference buildBootCachesForDisk:forcing:]: 1

fseventsd: disk logger: failed to open output file /Volumes/PNY4GB/.fseventsd/0000000000769ff7 (No such file or directory). mount point /Volumes/PNY-4GB/.fseventsd

Don't take anything for granted!

Not that it's guaranteed to help, but shutting down and restarting is THE most basic troubleshooting step and should never be written off as a possibility.

I fired up my old~ancient iMac DV SE running Mac OS 9.2 to see if the thumb drive would be recognized and mount. It did.

So, clearly something is/was awry with my Intel iMac. And, as you point out, shutting down and restarting is always the first step to remedy petulant behavior in Mac OS X. Done and done.

The thumb drive appears, none the worse for the experience.

So, once again, merci and a tip of the hat for the recommendation.

Always happy to help.

(At least I didn't recommend repairing permissions. )

That didn't even appear as a possibility in Disk Utility ... maybe because the drive's formatted as MS-DOS FAT.

Lots of black magic goes on when mounting and dismounting hard drives. Lots of kernel calls, lots of tightly controlled system calls. So when something goes wonky, it OFTEN requires a reboot to fix, simply because the system has a knot in a very complicated mechanism that it simply has no hope of getting untied regardless of what you do.