Slow Mac SSD transfer on MacBook Pro to WD USB 3 drive

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Level 1

60 points

Slow Mac SSD transfer on MacBook Pro to WD USB 3 drive

I had an issue with transferring data from a WD 4 TB (WDBYFT0040BRD) to another WD 4 TB (WDBYFT0040BRD) drive a few months ago.

I ended up having to replace the drive under warranty after 71 hours had passed since I started the transfer and only 1.28 TB had been copied out of 3.18 TB to be copied.

I was sent a new one and the same problem is happening again.

This time, I am trying to transfer 2.8GB of data from the Mac's internal SSD to the new WD drive.

At first MacOS states it will take less than a minute and shows that half a GB is copied very quickly onto the new drive within seconds!

But a third of the way through, it slows down dramatically and after a while 1 minute turns in 2, 3, 4, 7, 8 minutes and it's not even able to copy half of the data.

This is clearly not an issue with marketing from the manufacturers at this stage. And it's happening on a replacement drive. I am not trying to copy TBs of data, only 2.8 GB...

Could this be MacOS? Or something else more obscure?

Posted on Nov 13, 2021 8:11 AM

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Answer 1

steve626

Level 6

15,665 points

Nov 13, 2021 12:09 PM in response to lukatibo

Lots of factors can come into play. Normally these copies just happen smoothly.

(1) What year is the Macbook Pro. On Big Sur, latest version?

(2) What type of internal drive, SSD, mechanical HDD?

(3) How are the external drive(s) connected to the Mac? Is there an adaptor or hub involved? Other cables? What type of connection (thunderbolt, USB-C, USB 3, USB 2 ...)?

(4) How are the external drives formatted? APFS, HFS+, something else.

(5) Are you using the drive manufacturer's disk tools utilities?

(6) Do you have any third party (non-Apple) anti-virus, security, network safety/monitor, or other similar software, tools, extensions installed?

(7) What type of files are being copied? Data, image files, video, other? Copying certain system files, comprised of thousands of tiny files, can be excruciating slow, while normal copying is typically much faster.

I use those same models of external drives all the time. More than two dozen, to store and transport raw and jpeg image files for a professional photographer. On modern Macs with USB 3 or thunderbolt I will see typically 100 MB/s when copying from an internal SSD and for copies from one such external drive to another, on a modern Mac, maybe 80 MB/s.

You may want to boot into Recovery (COMMAND-R) and run Disk Utility First Aid on both the internal drive, and then on the external drive. If those both check out, next step could be the run DriveDX extended (long) test on the internal and external drives, to check their hardware.

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Answer 2

Ronasara

Level 6

15,553 points

Nov 13, 2021 4:49 PM in response to lukatibo

In addition to the fine comments posted above, I would ask you to confirm how the WD drive is being accessed. Incidentally, in the past I have found that some drive manufacturers, like WD, ship their drives with their own maintenance apps installed. I have found them to be highly problematic. If it has not been removed, I would remove it. Any formatting should not be done with those apps, according to my experience.

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Slow Mac SSD transfer on MacBook Pro to WD USB 3 drive

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