Need help troubleshooting strange USB stick slowness on my Mac Mini: it's effectively unusable, only USB flash memory sticks are affected

[saldin]

It's been happening since I purchased it, but because I seldom use USB sticks, I haven't paid it too much mind... But today I absolutely needed to use a USB stick and it was a pain; I had to use another Mac just to retrieve and save files there because I was pressed for time. I decided I have to fix this ASAP.

This is how it looks like: saving 2.2 GB to the USB stick is estimated to take about 6 hours.

The USB stick is nothing extraordinary, a Kingston USB 3 stick with 32 GB capacity. I have 4 of them and they all behave the same way.

I also have a 8 GB PNY USB 2.0 stick and the experience is the same as the Kingston sticks, so I don't think the USB technology is the problem here.

I've tried several formats (FAT32, ExFAT, HFS+) and there's no difference, so I don't think the disk format is the problem either.

I find strange that I have a couple of USB hard drives that have no such problem. They have USB-A connectors just like the Kingston and PNY sticks, so I don't think the USB-A ports are faulty.

Less than a minute to copy the exact same folder that would take 6 hours on the Kingston flash stick.

The USB sticks are not faulty. I connected them all to another Mac and to a Windows laptop and they work perfectly. They only have problems when I connect them to my Mac Mini.

I have no idea how one USB mass storage device can work (hard drive) and the other (flash) cannot.

Now, I have been using Macs for close to two decades, and each new one has received all the data from the previous one via Migration Assistant. I've had trouble before with migrated legacy printers that prevented the system from sleeping... and since I've used interoperability software like Parallels Desktop and Paragon's NTFS-For-Mac, I figure that a poor uninstallation process could be messing with my USB ports?

I don't know how I could start troubleshooting this issue, and I need help. Thanks in advance.

 

[chrfr]

Have you checked in System Information to confirm if these flash drives are actually connected at USB 3.0 speeds? I've also had many flash drives that slow way down because they got very hot while copying.

 

[saldin]

Have you checked in System Information to confirm if these flash drives are actually connected at USB 3.0 speeds? I've also had many flash drives that slow way down because they got very hot while copying.

Yes. The USB 3.0 stick gets 3.0 speeds, and the USB 2.0 stick gets 2.0 speeds. Both are connected directly to the Mac Mini back ports without any hubs.

I don't think the temperature is the root cause in this case, as they were connected only that moment and it would be unlikely that they would get unbearably hot in just a handful of minutes. I would also be able to tell when handling them.

 

[Fishrrman]

OP:

The info you posted in reply 3 above (indicating "speeds")... well, that's "not enough" to indicate real-world speeds.

Download the free BlackMagic Disk Speed Test, and try your flashdrives using that.
Post the results you get here.

If you want fast transfers between computers using an "intermediate drive", then a small SSD (128gb) is dirt-cheap and will be much faster.

 

[NoBoMac]

They’re flash drives, been seeing this type of thing forever. Basically, just because it says USB 3 or has a reputable name on it, memory technology, controllers, how connected, all impact performance.

Eg. Wide range of performance here. One brand shows up twice and slowest one of theirs has half the performance of their best one.

Best Flash Drives 2025: Fast, Spacious, Pocketable USB Storage

The best flash drives today are much faster and more spacious than they used to be.

www.tomshardware.com

From 2013, but bigger list and shows even more dramatic differences. Eg one model of Kingston is near the top but another has 1/3rd the performance.

31 USB 3.0 Thumb Drives, Tested And Reviewed

It's hard to believe that the fastest USB 3.0-rated thumb drives can outperform the hard drive in your desktop PC. On the other hand, the slowest models shouldn't even be allowed USB 3.0 branding. We test 31 different drives to determine the quickest.

www.tomshardware.com

And as both point out, what you’re copying can make a difference: many small files vs larger files for example.

Like @Fishrrman pointed out and the first link mentions, if speed is important, a small SSD will be much faster and still be wallet friendly.

(I rarely need to move/copy anything with a flash drive, and usually a file or two, so no problems. When more data, zipping it first and copying the zip helps speed it up vs doing a folder of many small files)

 

[spatlese44]

0.8 Mb/s is 600x slower than USB 2.0. Something is wrong.

 

[worldvirus]

Is this a M4 Mac Mini?
I am starting to suspect there is something wrong with the USB ports on all or some M4 mac mini's.
I've encountered some very strange behaviour, drive not mounting, usb keyboards randomly working/not working.
I don't know if this is related to you

USB problem/Thunderbolt on Mac mini M4 - Apple Community

discussions.apple.com

I'd be contacting Apple if it's still under warranty.

 

[Adora]

Is this a M4 Mac Mini?
I am starting to suspect there is something wrong with the USB ports on all or some M4 mac mini's.
I've encountered some very strange behaviour, drive not mounting, usb keyboards randomly working/not working.
I don't know if this is related to you

USB problem/Thunderbolt on Mac mini M4 - Apple Community

discussions.apple.com

I'd be contacting Apple if it's still under warranty.

I can confirm it's not only the Mini, the M3 iMac is even worse. And it's also the Thunderbolt ports if you put a dock on them. But Thunderbolt drives never auto-eject only USB.

I am now on 15.5 Beta 4 and there are less or no keyboard and mouse problems at the moment at least since I don't use the TB4 docks anymore and instead a hub on one of the front ports. The iMac had problems with all kind of USB-hubs I tried and is not in use at the moment. TB4 docks have similar problems on the Mini and iMac.

For me it all started with the 15.1 or 15.2 betas on the iMac. The 15.0 betas had less to no problems. I started directly with Developer Beta 1. The Mini got some 15.3 Beta already I think, it's in use since early January.