Big Sur Disconnecting My External HDD

This is crazy. I put a USB-powered Seagate HDD on my Mac Mini and set it up as my Time Machine disk. All was good for a few months and then it started exhibiting this problem. Based on 'whatever' I replaced that with an externally powered USB drive (8TB Seagate), and it, too, worked fine for about a month, and now this:

(typical -- starting about a week ago)

I have tried Disk First Aid (repeatedly) and reformatting the drive, and yet the problem continues.

My Mac Mini is running fully updated Big Sur, and the drive is directly connected to the Mini (not through a hub or anything).

Since it can occur so frequently, I can see (in Time Machine) that the drive does appear to disconnect/reconnect, but I'm eventually getting 'good' backups.

What is the resolution?

I just posted a similar topic, adding that when the external HDD disconnect happens, Bluetooth is disabled, peripherals disconnect, and the iMac doesn't respond even after connecting a wired keyboard and mouse. I have two external HDDs, each with separate TimeMachine backups, and separate volumes for data. Only one of the HDDs presents this problem, ejecting the TWO volumes (data and TM).

I'm on senior level tech support right now. I've been on support for the past week, off and on, because of this very problem. One of my external hard drives, a new one, has already had to be replaced because it started grinding. I just bought my iMac in January. It came with Big Sur. So far, no tech support person, for Apple, acted like they knew there was a problem with Big Sur causing disconnects with external hard drives. Yet, your post is like many others on here saying that there's a problem. Who is looking at these concerns? I returned the new external hard drive to Best Buy and had a discussion with a Geek Squad guy, while there. He knew about it! He told me that there's a problem with Big Sur and external drives. Really? Geek Squad is aware but not the APPLE support people? Clearly, the issue is not being resolved and apple support isn't being allowed to acknowledge that they know it's a problem. It smells like a cover up until they figure it out. So, don't expect answers anytime soon from tech support. We are stuck.

Is not helping. I tried several times.

I want to back up to Catalina now, but I am scared, if the ports are not working well, I will start reinstalling from Time Machine on HDD, perhaps it could lead to a complete breakdown.

So, I'm stumped.

Thank you so much for this my WD external drives have been driving me crazy, I'm using an Imac with Big Sur and tried this yesterday and so far they are all fine and showing all files and the icons are all working and not disconnecting.

Glad to hear both of you got it all worked out.

My case is still with engineering. I haven't heard anything from them. I've checked status online a couple of times, but couldn't find anything relating to it online today (perhaps it's some kind of glitch).

I've never had Trend AV on my Mac. I use Malwarebytes, which by the way, the support tech used to check the file system.

Since my initial post, I've replaced my USB 3.0 drivebay with a TB3 drivebay (Thunderbay 4 from OWC-raid capable). All bays are filled and it works perfectly.

The G-Drive Mobile pro tech told me this model of TB3 ssd was tested on Big Sur with no issues...

I plugged the SSD into the Thunderbay 4 TB3 in/chain port, and it worked for a couple days. Then it started the arbitrary disconnects again.

I am curious as to why it worked for a couple of days after I plugged it into the Thunderbay 4...

I am also curious why all of my other TB3 peripherals work fine (Thunderbay 4, Caldigit TB3 dock and everything connected to it, and a TB3 eGPU with Radeon Vega 64). No drivers required for any of them.

This all started when I upgraded to Big Sur, but with all that's happened since, I'm not sure if Big Sur is the issue. I am sure, that whatever it is, was initiated by the upgrade.

This G-Drive Mobile Pro 1TB TB3 SSD has been replaced 3 times (the current drive was brand new when it arrived still in the retail packaging). Behavior was the same for all 3 drives.

Apple support started out being responsive up until the last month or so... I need to find out why they fell off.

As much as I hate to, I'm starting to consider rebuilding the Mac. I can't use time machine backups, so it would be from scratch. What a pain...

Does anyone know if there is a way to restore only applications to a new build?

I just finished rebuilding my Mac from scratch. No applications installed and still the TB3 drive exhibited the same behavior. All my other TB3 devices are working normally.

Somebody is full of it, either Apple (I actually haven't heard from them on this issue since it went to the engineering team-which about a month ago), or the G-Drive Mobile Pro team. Maybe both...

I am having the same problem with Big Sur 11.2.3: I get the message that the external hard drive has not been ejected properly after the iMac has been in sleep mode. To complicate things, it does not seem to happen every time. Still very annoying and disquieting – is data integrity on the external SSD endangered?

Does Apple care about this at all?

Apple engineers couldn't find anything in the OS that might cause this, and WD/HGST is clueless. I am running Malwarebytes (paid). I've turned it off and no change.

The drive worked perfectly in Catalina. As soon as I updated to Big Sur, that's when the disconnects started. I rolled back to Catalina last week, and it still happened, that I don't understand...

When I reinstalled Big Sur (no other apps installed), it took about an hour before it started happening again.

I'm going to try safe mode one more time, if that doesn't work, I return the drive 1 more time (it will be the 4th) and hope for the best, and if it still continues this behaivor, I'm done with G-Technology altogether.

That's interesting, because when my drive was working it was connected to a Caldigit TS3 Plus which is a TB3 dock when Catalina was installed. I never actually connected it directly to the Mac.

When the issue started I tried to connect it to anything and everything it would connect to (Mac, dock, TB3 drivebay), none of it helped. As I've rebuild the Mac from the ground up with both Catalina and Big Sur, I'm giving the dock another shot. Can't hurt...

Well, it looked promising... After connecting to the dock, it was about 4 hours before the first disconnect. After which, it happened maybe once per hour.

I guess the question now is, why is the behavior so different when the TB3 SSD is connected to a dock?

I have an OWC 4 drive TB3 Drive bay connected directly to the Mac Mini, and It has never had a connectivity issue.

I'll connect the SSD to the upstream drive bay port and see what happens.

2+ days no issues, and guess what... it happened again this morning.

I'm sending it back via RMA. This particular replacement was brand new... I'm sure the next will be refurbished. I don't really expect it to work, but I did pay quite a bit for the drive, so I'm not going to just chuck it. Perhaps I'll turn my 2018 Mac Mini into a windows box...

In my case this is just too random. No matter if it's plugged directly into the Mac or into the powered TB3 dock or TB3 Thunderbay 4, it still disconnects...

If by some miracle the replacement behaves any differently, I'll update.

ok so I think you on to something I just got my new laptop with M1 and my external hd was working just fine till I installed bunch of Adobe app ...as Photoshop and Lightroom and Premiere ...and exactly about the time installing Premier and when it was doing this thing with Rosetta the comp was acting bit strange , I don't recall precise actions but it was strange ... but because all my work is on external drives this is unacceptable to me and then I find out M1 can't run older OS I'm mad ! Anyway did you have any luck fixing this problem? Thank you !

I received the replacement drive yesterday. No change. That drive cost me a bit more than $300, worked for about 16 months, now for some reason (Apple engineering and G-Technology/Western Digital pointed the finger at each other), not one of the 4 replacement drives works with my 2018 Mac Mini.

You don't have to tell me a 100th time, I know when to quit. I'm done, no more G-Tech/WD for me. As for Apple, I am certainly not happy with them. I can't fault them for trying, and perhaps they are correct, but it's not the 1st time they haven't been able to solve an issue I asked them to help with.

I do believe it is not the hardware (the drive did work for over a year), but it had to be something. When I rolled back to Catalina (which was installed when the drive worked), it still randomly disconnected (even when connected to a powered source). I probably didn't roll back to the same Catalina build...

I do have Time Machine backups back to October last year... I may decide to roll back to the oldest Time Machine back up just to see what happens, which probably wouldn't do me any good because, even if it did work, I'd be stuck there with the eGPU issues and no path forward. Perhaps I'll do it as an experiment. Perhaps...

Either way, no more G-Tech/WD for me.

Update: I just confirmed, I did roll back to the same build of Catalina. I guess there's no reason to experiment after all.

I have the same problem.

• Brand new Mac Mini M1 with Big Sur.
• External WD 5TB passport drive (which I've tried formatting in EXFAT and HFS+ Journaled and NFTS with no improvement).
• The drive is read OK on start-up or upon installation (takes sig longer to read than in windows).
• Then, after about an hour or so the drive seems to disconnect. I've tried remounting in in disk utility with no success. Finder seems to show the drive, but no files show up. WhenI try to eject the drive it tells me the drive is still active (even although I can't see it and have no programs open).
• Preferences is set to display external drives
• The drive opens quickly and with no problem in windows (EXFAt and NFTS that is)
• I've tried a different drive with the same result.

This is my first time using a Mac and I was very excited about the M1 chip, but have found this enormously vexing to the extent that I'm considering selling the Mac and going back to a PC.

Any help would be greately appreciated. Many thanks