OS 10.7 - OS X Lion will not read external hard drives and USB flash drives

tompam · tompam #1 (**permalink**)

07-28-2011, 08:29 AM

The other day I bought the OS X Lion from the App Store and it installed successfully on my Macbook Pro. Today for the first time I connected my external hard drive to my laptop but it couldn't be detected. I also connected another of my external hard drives as well as my USB flash drives and none of them could be detected or read by my laptop after I installed Lion. Can anyone help?

louishen · louishen #2 (**permalink**)

07-28-2011, 09:00 AM

Is there a file called IOUSBMassStorageClass.kext in System/Library/Extensions/

tompam · tompam #3 (**permalink**)

07-28-2011, 10:53 AM

I couldn't find it. Is it significant? Am I the only one with this problem?

RavingMac · RavingMac #4 (**permalink**)

07-28-2011, 11:17 AM

Until Louishen gets back to you on the KEXT file, you might try having Spotlight ignore the external drives. Been doing some looking and apparently some third party software in particular causes Spotlight Indexing to hang, causing Lion to unmount the drives.

tompam · tompam #5 (**permalink**)

07-28-2011, 11:37 AM

I'll try this. Thanks.

harryb2448 · harryb2448 #6 (**permalink**)

07-28-2011, 06:42 PM

Works perfectly with Cruzer SanDisk Slice.

Can't help with external drive as on a Mac Pro backup drive is installed in position two and works well.

osxx · osxx #7 (**permalink**)

07-28-2011, 06:52 PM

Works great on my SanDisk Cruzer 4GB.

tompam · tompam #8 (**permalink**)

07-28-2011, 06:55 PM

I tried as many brands of external hard drives and USB flash drives with the same results. None of them will mount with Lion.

bobtomay · bobtomay #9 (**permalink**)

07-28-2011, 08:10 PM

My question would be: What do you mean by it's not mounted?

It doesn't appear on the Desktop?

It doesn't appear on the Sidebar in Finder?

It doesn't appear in Disk Utility?

joeg679 · joeg679 #10 (**permalink**)

07-28-2011, 09:08 PM

Quote:

Originally Posted by tompam

The other day I bought the OS X Lion from the App Store and it installed successfully on my Macbook Pro. Today for the first time I connected my external hard drive to my laptop but it couldn't be detected. I also connected another of my external hard drives as well as my USB flash drives and none of them could be detected or read by my laptop after I installed Lion. Can anyone help?

I'm having the exact same problem, did you fix yours?

joeg679 · joeg679 #11 (**permalink**)

07-28-2011, 09:15 PM

Quote:

Originally Posted by tompam

The other day I bought the OS X Lion from the App Store and it installed successfully on my Macbook Pro. Today for the first time I connected my external hard drive to my laptop but it couldn't be detected. I also connected another of my external hard drives as well as my USB flash drives and none of them could be detected or read by my laptop after I installed Lion. Can anyone help?

Ok, I left the hard drive plugged in for about 8 minutes and the computer finally recognized it. Before lion, it would see it instantly. Try leaving it plugged in for a little while

randalthor · randalthor #12 (**permalink**)

07-28-2011, 10:10 PM

Quote:

Originally Posted by joeg679

Ok, I left the hard drive plugged in for about 8 minutes and the computer finally recognized it. Before lion, it would see it instantly. Try leaving it plugged in for a little while

Spotlight was possibly indexing it. Shouldn't take that long to recognize the second time around. Try again now that it's been recognized once?

tompam · tompam #13 (**permalink**)

07-28-2011, 10:39 PM

Quote:

Originally Posted by bobtomay

My question would be: What do you mean by it's not mounted?

It doesn't appear on the Desktop?

It doesn't appear on the Sidebar in Finder?

It doesn't appear in Disk Utility?

It doesn't appear on the Desktop, the Sidebar, or the Disk Utility. I'll try joeg679's suggestion of leaving the external hard drive connected to the laptop for 8 minutes or more until it appears. I hope it works.

tompam · tompam #14 (**permalink**)

07-28-2011, 10:40 PM

Quote:

Originally Posted by joeg679

Ok, I left the hard drive plugged in for about 8 minutes and the computer finally recognized it. Before lion, it would see it instantly. Try leaving it plugged in for a little while

I'll try this. Thanks.

dtravis7 · dtravis7 #15 (**permalink**)

07-28-2011, 10:44 PM

Is this a new Mac? I have never had a Flash drive that would not mount unless the drive was dead. Never. My Dell refused to mount my 2GB Kingston, 2 dells in fact but it mounted instantly on my Macs at the time.

Not sure what to say. How are these drives formatted? You say Lion is the cause. I have 6 external drives, plugged in USB2, FW400 and FW800 and all show right up on my iMac under Lion. I tried 8 Flash drives and every one shows right up.

louishen #2 (permalink)
Member Since: Oct 22, 2007 Location: London Posts: 8,684 Mac Specs: Mac Mini Core i7 2012 \| White 2009 MacBook 2 Ghz \| 733 Mhz G4 Quicksilver	07-28-2011, 09:00 AM Is there a file called IOUSBMassStorageClass.kext in System/Library/Extensions/ Member of the Month September 2008 & August 2012 \| Found advice useful? – use the rep system
	QUOTE Thanks

RavingMac #4 (permalink)
Member Since: Jan 07, 2008 Location: In Denial Posts: 6,848 Mac Specs: 4GB Mac Mini 2012, 13" MBA, 15" MacBook Pro OSX 10.7, 32 GB iPhone 3GS, iPad2 64gb 3G	07-28-2011, 11:17 AM Until Louishen gets back to you on the KEXT file, you might try having Spotlight ignore the external drives. Been doing some looking and apparently some third party software in particular causes Spotlight Indexing to hang, causing Lion to unmount the drives. Of course, I know everything . . . I just can't remember it all at once.
	QUOTE Thanks

harryb2448 #6 (permalink)
Member Since: Nov 28, 2007 Location: Nambucca Heads Australia Posts: 14,265 Mac Specs: iMac i5 2.7GHz OS X.8.3	07-28-2011, 06:42 PM Works perfectly with Cruzer SanDisk Slice. Can't help with external drive as on a Mac Pro backup drive is installed in position two and works well. *Hang on to those original install discs like grim death! Using OS X.7 or later make a bootable USB thumb drive before running Installer!*
	QUOTE Thanks

bobtomay #9 (permalink)
Member Since: Dec 22, 2006 Location: Texas, where else? Posts: 22,048 Mac Specs: 15" MBP 2.33 C2D 256 4GB, MBA 13" i7 1.8, MB 2.0 2GB, Nano 4th, 3GS, iPad 1	07-28-2011, 08:10 PM My question would be: What do you mean by it's not mounted? It doesn't appear on the Desktop? It doesn't appear on the Sidebar in Finder? It doesn't appear in Disk Utility? I cannot be held responsible for the things that come out of my mouth. In the Windows world, most everything folks don't understand is called a virus.
	QUOTE Thanks

dtravis7 #15 (permalink)
Member Since: Jan 04, 2005 Location: Modesto, Ca. Posts: 25,895 Mac Specs: iMac C2D Late 2007 20" with 10.8.3, Macbook Santa Rosa 4GB Ram OSX 10.8.3	07-28-2011, 10:44 PM Is this a new Mac? I have never had a Flash drive that would not mount unless the drive was dead. Never. My Dell refused to mount my 2GB Kingston, 2 dells in fact but it mounted instantly on my Macs at the time. Not sure what to say. How are these drives formatted? You say Lion is the cause. I have 6 external drives, plugged in USB2, FW400 and FW800 and all show right up on my iMac under Lion. I tried 8 Flash drives and every one shows right up. ...Dennis Mac-Forums Community Guidelines
	QUOTE Thanks

OS 10.7 - OS X Lion will not read external hard drives and USB flash drives

Internet Services

Web Development

Digital Marketing

Consumer Tech

tompam #1 (permalink)
Member Since: Jul 28, 2011 Posts: 29 Mac Specs: iMac, Macbook Pro, Apple TV, iPhone 4, iPad 2	07-28-2011, 08:29 AM The other day I bought the OS X Lion from the App Store and it installed successfully on my Macbook Pro. Today for the first time I connected my external hard drive to my laptop but it couldn't be detected. I also connected another of my external hard drives as well as my USB flash drives and none of them could be detected or read by my laptop after I installed Lion. Can anyone help?
	QUOTE Thanks

tompam #5 (permalink)
Member Since: Jul 28, 2011 Posts: 29 Mac Specs: iMac, Macbook Pro, Apple TV, iPhone 4, iPad 2	07-28-2011, 11:37 AM I'll try this. Thanks.
	QUOTE Thanks

osxx #7 (permalink)
Member Since: Jan 19, 2008 Location: houston texas Posts: 3,950 Mac Specs: 15 MacBook Pro 2009 32GB iPad 4 32GB iPhone 5 Apple TV 3 AEBS/AE	07-28-2011, 06:52 PM Works great on my SanDisk Cruzer 4GB.
	QUOTE Thanks

tompam #8 (permalink)
Member Since: Jul 28, 2011 Posts: 29 Mac Specs: iMac, Macbook Pro, Apple TV, iPhone 4, iPad 2	07-28-2011, 06:55 PM I tried as many brands of external hard drives and USB flash drives with the same results. None of them will mount with Lion.
	QUOTE Thanks

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Advice on external hard drives...	credential	Other Hardware and Peripherals	4	12-28-2010 08:50 PM
(my opinions) How little USB flash drives could replace CDs/DVDs	the8thark	Schweb's Lounge	9	12-17-2010 05:47 PM
External hard drives wont mount	vnote	Other Hardware and Peripherals	9	08-15-2009 02:32 AM
Cannot partition external USB hard drives	hardbap	Switcher Hangout	4	08-29-2008 09:19 AM