USB Thumb Drive Not Mounting With Mavericks

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OzziesMAC Author

Level 2

183 points

USB Thumb Drive Not Mounting With Mavericks

I have several Thumb drives (FAT32) that no longer mount on my iMac running Mavericks.

The thumb drives do not show up in finder nor do they show up in disc utilities.

The USB bus still seems to work since other USB devices seem to connect to it, but none

of the thumb drives do. I have done an SMC and PRAM reset with no luck. I do not have

TUXERA nor NTFS-3G so nothing their to disable.

I do have a Mac Mini running Mountain Lion and all thumb drives do work with that.

Out of ideas here.

Posted on Jul 13, 2014 7:53 AM

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Answer 1

Best reply

MrHoffman

Community+ 2024

Level 10

116,637 points

Jul 13, 2014 8:48 AM in response to OzziesMAC

This could be a problem on the local USB bus configuration, with the OS X installation or configuration, or it could be a problem with the USB bus.

Given the thumb drives do work on a different system, it's apparently something local to this Mac, and it's certainly possible that the USB interface on this Mac has failed. But given that other USB devices work here — what sorts of other USB devices? — the USB bus seems at least partially functional, which implies it's something local to your login, or something local to your OS X installation.

Are there any add-on anti-virus or anti-malware "tools" installed? if so, please remove those immediately using the tool-specific removal mechanisms and processes, reboot, and test again.

To check the USB bus, remove all hubs and all other external USB devices from this Mac, reboot, connect one of the thumb drives directly to the Mac, and try again.

Try a different and newly-created login, and see if the flash drives work there.

To check the local OS X installation, see if booting this Mac from the recovery partition (if one is present) or booted from another (external) OS X disk allows access to the thumb drives. You can install OS X on an external disk from other Mac, if you can get an external bootable non-flash-storage-device working. This check can use Disk Utility when booted from the "other" OS X installation.

Failing that...

Is there anything in common among these failing USB disks? Same brand and model? Or a mixture of different thumb drives?

Are the OS X systems involved both similar configurations, or are they very different versions?

Do have a backup or three of this system. Just in general.

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Answer 2

OzziesMAC Author

Level 2

183 points

Jul 13, 2014 9:06 AM in response to MrHoffman

But given that other USB devices work here — what sorts of other USB devices?

I have 2 external hard drives that work on the very same USB port and an external blu-ray drive as well.

Are there any add-on anti-virus or anti-malware "tools" installed?

None. Never have.

To check the USB bus, remove all hubs and all other external USB devices from this Mac, reboot, connect one of the thumb drives directly to the Mac, and try again.

Everything re-connected except for the thumb drives. External hard drive and Blu-ray drives popped right up but no USB flash drives.

Try a different and newly-created login, and see if the flash drives work there.

I used the Guest login and the same thing, everything works except the Thumb drives.

To check the local OS X installation, see if booting this Mac from the recovery partition (if one is present)

None is present.

or booted from another (external) OS X disk allows access to the thumb drives.

I have en extern HD that is blank, but I do not know how to install Mavericks on it then run it.

Is there anything in common among these failing USB disks? Same brand and model? Or a mixture of different thumb drives?

They are all FAT32, other than that no I have Cruzer, Kingston and PNY brands. 2GB 4GB and 16GB.

Are the OS X systems involved both similar configurations, or are they very different versions?

Mac Mini is Mountain Lion and has no issues with the thumb drive.

Intel iMac is Mavericks and my Mac Book Pro is Mavericks. Neither one of them can mount my USB sticks.

Thanks for your complete reply, you had some items that I did not try but unfortunately it did not help yet.

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Answer 3

den.thed

Level 9

77,176 points

Jul 13, 2014 9:34 AM in response to OzziesMAC

Is Mavericks up to date...?

I ask because, I was having some minor mounting and un-mounting issues in 10.9.2 and 10.9.3, that seem to have cleared up in 10.9.4.

Additionally if you have been updating Mavericks using the App Store like most folks do..? Then try downloading and running the > OS X Mavericks 10.9.4 Update (Combo) over the top of the App Store update to see if that helps clear up your mounting problem.

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Answer 4

OzziesMAC Author

Level 2

183 points

Jul 13, 2014 9:57 AM in response to den.thed

Just did the combo update, and still no USB thumb drives being recognized.

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Answer 5

Jul 13, 2014 2:31 PM in response to OzziesMAC

Please ensure that no external USB devices, no external USB cables, and no BluRay player are present when testing. Just one flash drive in the USB port.

Here is how to create an external recovery disk partition.

To install OS X onto a different disk, download the OS X Mavericks kit from Apple, launch it, and — when it starts up and asks you where you want to install — tell it to install on a disk other than your boot disk.

For an inventory of what's been installed, you can download and run and post the output of Etrecheck — some of the folks around are pretty clever at getting weird software installed onto OS X unfortunately, and that add-on software can lead to odd problems.

Before running Recovery Disk Assistant or loading OS X onto an external disk or other operations, you will want to make sure you have a current, complete backup of your disk — the most important data here is your own data, and your own data is unfortunately the most difficult to recreate if something should go wrong here and there are no valid, current backups available.

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