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Slow copy speeds to USB in Lion

Hi all, just upgraded from SL to Lion and noticed now when i copy large files like 300mb+ to a USB key its taking ages (about 4 mins) to copy where is SL it was much faster. THe key is formatted in FAT32 for playback on PS3 but this has always been the same and SL was fine.

I also notices i dont get the blue animated progress bar when copying its seems to stumble along very blocky and is not as fluid.

Copying FROM the key to the Mac HDD is fine all is as normal. Also copying to a 1TB WD Ext HDD with Time machine is also fine.

System is bang up to date so any ideas anyone or is this something i have to live with until an update is release?

iMac, Mac OS X (10.7)

Posted on Aug 17, 2011 12:34 PM

99 replies

Aug 6, 2013 5:38 AM in response to Sean Akers

THIS WORKED FOR ME.

Context: MBP 15" late 2009, running OS Lion.

Task: copying a SuperDuper! benchmark clone from one external drive to an encrypted disk image on another external drive.

Problem: transfer speed is about 5MB/s, task will take 20+ hours.

After reset of PRAM and SMC (as descibed by Sean Akers), transfer speed is 200-500 MB/s.

Thanks Sean!

DocPB

Level 1

0 points

Sep 11, 2013 7:35 PM in response to ritchiefromnottingham

If you're getting slow USB transfers, chances are you have FileVault on, which means your computer has to read, decrypt, then transfer the file. Turn off FireVault and everything will be fine.

Sep 11, 2013 11:35 PM in response to DocPB

> > >

Sep 11, 2013

Re: Slow copy speeds to USB in Lion

If you're getting slow USB transfers, chances are you have FileVault on, which means your computer has to read, decrypt, then transfer the file. Turn off FireVault and everything will be fine.

<<<

No, Doc, I will not allow you to hijack this thread and make it about FileVault. This issue has NOTHING to do with FileVault.

DocPB

Level 1

0 points

Sep 12, 2013 7:10 PM in response to DaddieMac

It's not a hijack. t's an actual solution. My MacBook air was taking ages to transfer files from the HD to a 1TB USB 3.0 drive formatted as NTFS. Even 1GB was taking over 5 minutes to transfer. After turning off FireVault, th transfer speeds were 10 times faster. Obviosuly this worked for me, it may work for a few others as well.

Dansyacht

Level 4

2,135 points

Oct 29, 2013 4:38 PM in response to Patrick Kinsella

Patrick Kinsella wrote:

After reset of PRAM and SMC (as descibed by Sean Akers), transfer speed is 200-500 MB/s.

Thanks Sean!

Could you post a link to this procedure?

Oct 29, 2013 8:57 PM in response to Dansyacht

Sean Akers post is on page 3 of this thread. This is what he wrote:

"Step 1.

Shut down your computer.

Step 2.

With powe off, SIMULTANEOUSLY press shift-control-option-power and hold for 5 seconds. Release SIMULTANEOUSLY. The computer should not power on.

Step 3.

Reset PRAM. Hold P-R-Command-Option as you startup until you hear the startup sound a second time. Release.

My speeds returned to normal. Before this, 7GB transfer on USB took a little over 2 hours. Now, it took about 9 minutes. Perfect."

Jul 10, 2014 10:36 PM in response to Patrick Kinsella

Yes, resetting PRAM also fixed slow USB transfer rates for me as well...

Back up to 20MB/sec which is what the drive benchmarks at with Blackmagic. So all is good.

zackg007

Level 1

8 points

Jan 11, 2015 6:08 AM in response to Sean Akers

Thanks so much. This helped and I was having this issue with 10.9.4.

I know this is a lion thread but thought I'd try anyhow. Totally worked. At least doubled the speed. Thanx

Apr 21, 2017 7:37 AM in response to visarya

4 years later and this solved my super slow copy speeds on macOS Sierra

Slow copy speeds to USB in Lion