External SSD Disconnects Repeatedly Mac Mini M1 (Big Sur)

Solved!

I had the same issue, and I solved it by changing the disk sleep settings in Terminal. I couldn't go to Energy Saver prefs because on Monterey I don't see the option to not put disks to sleep. So, I followed Item 2 on this page.

Details:

My M2X SSD enclosure from MyDigital SSD would intermittently disconnect. Sometimes in the middle of using it; sometimes when idle. It only did this on my M1 mini, and not when connected to my older Intel iMac (but I'm not sure of that Mac's disk sleep settings). I already tried swapping the USB C cable, but that did not matter. It's a JMicron Tech chip in the enclosure.

This is the most common solution: Choose

System Preferences… > Energy Saver

Check the box for 

Prevent computer from sleeping when the display is off

(There is no need for the computer to go to sleep, since it’s not running on battery.)

If this doesn’t solve the problem the first time, try toggling the setting. Check the box, close System Preferences, re-open Energy Saver, then uncheck the box. This resets a munged value in the .plist file.

This Terminal command is another way to make the change

pmset -a disksleep 0 

View man pmset in Terminal for details.

Hello!

I wish my solution will help somebody. I have M1 Mac Mini 512/8 with Satechi hub (inside it is Samsung EVO 860). And all was fine before last system update (now it is Monterey 12.4). After it external SSD disconnects 20-50 times at evening (I work with it only 2-3 hours a day). It was terrible 'cause I am a photographer and my photos on external disk. I just can't choose some photo 'cause SSD keep disconnects every minute! I read this thread and another on different sites and try all things that people recommends. It not helped (nor cables change or nor system sleep preferences). And I want to try another external hard drive to see will it happen with it. And it worked! I just connect to USB on front of Satechi station my old external Samsung HDD G2 and after that EVO860 not disconnects at all! With this solution I live near 3 weeks and it's all right.

Having updated to Big Sur 11.2 on 1 Feb, the problem, at least for me so far seems to have disappeared. Any change for you dschommer?

The only solution that works for everyone is to check Prevent computer from sleeping when the display is off.

This is a macOS bug and has been unfixed for more than a year.

I have no idea why but purchasing this cable worked for me. 48 hours with a stable connection.

https://www.amazon.com/dp/B005H3Q52C?psc=1&ref=ppx_yo2_dt_b_product_details

Hi there dschommer,

Thanks for using Apple Support Communities. It sounds like you have an external drive disconnecting when trying to write some files to the drive. Since this issue does not occur when using a different connection method, it may be the port or cord you are using. Check the port for any debris and try replacing the thunderbolt cord.

Try repairing the disk in Disk Utility as well. See how here: Repair a storage device in Disk Utility on Mac.

We hope this helps!

I guess that I had more to add to this.

Under the circumstances where the device is connected directly to the M1 Mac, the enclosure LED lights up solid, and Disk Utility appears to detect the drive, and one is presented with the options to eject, ignore or initialize the drive, it is possible to use DU to do the initialization. In these instances, DU will detect a 97TB drive size and the initialization will fail.

About as often, the enclosure LED may light up solid, and DU does not detect the internal SSD at all, even though the drive electronics will show up in SysInfo under TB or USD depending on the cable being used.

If, after the failed initialization attempt, the enclosure is immediately connected to the OWC hub, the device will connect normally (if it's the Sabrent Rocket inside the Sabrent enclosure) and show a healthy file system, with the previous content, and 2TB in size. That is, the initialization attempt did not touch the SSD.

If there is no drive inside the enclosure at all, the enclosure LED will not light up in any way, at least for the two that I've been using. Controller electronics will show up in the SysInfo panel, as appropriate.

The enclosure LED will never light if there is not drive installed. The enclosure LED will go solid if there is a drive installed when connected to the OWC hub. Often, the enclosure LED will light up solid only on a second connection to the M1; that is, connect the cable and nothing happens, disconnect and immediately reconnect and the enclosure LED will go solid.

If there is a drive, and if the LED blinks once, goes solid and then flickers, there is data connectivity and flow. In general, in my experience with the Rocket 4+ SSD and the two enclosure I have, this desired behavior will happen consistently only when the Sabrent Rocket is in the Sabrent USB-C enclosure and that is connected with a USB-C cable to the OWC hub.

All other bets are off.

I have the same problem with my MacBook Pro M1 and a 1TB Portable SSD (USB-C 3.2) from SanDisk. Initially I works, I load files, but when I try to open or move files it gives odd messages like "The Finder can’t complete the operation because some data in “Administration” can’t be read or written. (Error code -36)" goes blank and disconnects. After updating the computer it seems to stay connected, but still turns blank. I ordered a new similar SSD from SanDisk, with the same problem. I've changed caples and ports, and it works with my older external HDD and SSD. Seems to be a problem with the M1 and/or the operating system in relation to this new 2021 model SSD.

FYI, I have only used WD blue and black NVME drives all in trebleet TB enclosures. I have 3 and all work great on my Intel iMac and MBA M1. I agree that TB connections are finicky at best and sometimes reversing the cable (flip over) can help. I also I find different hubs can cause issues if connecting a drive to them. I had some issues using a Caldigit hub but zero issues using a Kensington hub.

Disable Sleep entirely, it’s unnecessary on later Macs, all pain, no gain. Check “Prevent…” in Energy Preferences and uncheck everything else. You can leave the display off time as is, unrelated to Sleep. It may not resolve entirely but good chance it’ll improve it. All the best.

The one drive I had would disconnect connected directly to the Mac. I finally moved it to my TB hub and now it appears OK.

Please contact Apple Support and report this issue, all have the same issues here!

Please everyone must contact Apple support via phone!

This issues a nightmare!!!

Phone Apple, yes. But also report this as a bug here:

https://feedbackassistant.apple.com

[Edited by Moderator]