External Hard Drive Missing After Big Sur Download

I have this problem too.... trying iBoysoft NFTS software. It is helping. I did have Tuxera and it is not working. I need to be able to write to my external drive! :-(

It's in the sidebar in the finders window, where Favorites, iCloud, Tags are listed. So make sure sidebar is turned on (go to View, then Show Sidebar).

Hi Apple support! I am having the same problem with my Macbook Pro and my Seagate 4TB external hard drive. It no longer shows up at the Finder, although I can see the disk with Disk Utility tool. But it can’t be mounted. This is unfortunate since I have tons of important files on that disk and also all my backups. I hope a fix is coming soon!

Same here. After installing Big Sur on my relatively new MacBook Pro (2019), my hard drives fail to show up. First it was one out of three, and now it is two out of three. No matter what I do (restart, shut down and start all over)...nothing seems to make them show up. They are on, through a powered USB hub, and I can see their blue operational lights. Disk Utility does not seem to see them either.

Anyone? Anything?

I keep my rotating EHDs formatted as OS X Extended (journaled). APFS is for SSDs.

If you don't have any files on you're Time Machine that you need you can erase it and start over with a fresh backup. I had to do that a while back as it TM wouldn't get out of the "preparing" phase. An erase fixed it up nicely with no problems since.

I upgrade to Bug Sur last night and I am having the same problem with my MacBook Pro and my Seagate 4TB external hard drive. It no longer shows up at the Finder or in Disk Utility tool or in Stellar Photo Recovery. I tried 6 different cables and 3 different USB ports with no luck. I updated to the latest driver for Big Sur and still nothing. Going to try another computer to see if I can upload the images to my cloud from there, but would like to use it since all my RAW images in Light room refer back to that disk.

Hi,

If your mac produced after 2017, T2 chip cause these kind of problems. I have been dealing different type issue which is related with the T2 chip since last week.

And last version of Big Sur 11.1 destroyed my MBP 2019 ...

Yes I agree, this is really amateur. You can disable T2 chip.

1- restart your mac

2- push down command+R

it will login to recovery mode. Top of the window you will ser the Utilities option, click startup security, in the next window click no security and allow booting.(to be helpfull not read all the discussion here maybe you have done it)

But the real problem is for the machintosh computers are when you update it, it also updates BIOS(different name in macs not BIOS). So that is the problem. It destroy’s firmware.

After the last update it burned my USB hub. And usbc ports stop working. Not able to charge it. Now my mac is getting “fixed” in apple service...

Windows is really shity OS but it does not touch BIOS.

Thanks! My old 2013 laptop had/has no problem reading and writing to my externals. It is the brand new 2020 MacBook pro that comes loaded with Big Sur that has the issue. I'm waiting impatiently for the 3rd party companies to update their software to read NTFS files.

I got the new 2020 MacBook Pro M1 13" and connected an external HGST hard drive formatted by a PC to ExFAT. It was seen but could not be mounted. What solution is needed for Big Sur to be able to read and write files on that external HD?

Apple Support had me reset System Management Control (SMC) and reboot, but this did not solve the problem.

The problem happened regardless of whether the drive was connected on its own via a Sabrent USB connector directly to the MacBook's USB port (with a C-to-A adaptor) or whether the drive was in a 2-bay Innatek dock connected via USB-A to a CalDigit TS3 multi-port dock that's connected via Thunderbolt 3 cable to the MacBook. The error showed up in a pop-up message from the Mac's Disk Utility app that said "Could not mount “{disk name}”. (com.apple.DiskManagement.disenter error 49223.)"

Apple tech support is looking into it. But if you have wisdom on this problem, I'm interested in what has worked for people with this problem (an external hard drive formatted by a PC as ExFAT is not openable).

Thanks!

My WD My Book, that worked with High Sierra, no longer is workable for Time Machine after I upgraded to Big Sur. The drive has to be unlocked, and the WD Drive Unlock app appears on Finder, but when I try to unlock I get the message "You must run the WD Drive Unlock CD associated with the drive you want to unlock". Trouble is, that CD is a virtual CD contained on the drive itself. I can go to Disk Utilities and find the Virtual CD and within it the Unlock app, which shows as "mounted" with the option to "unmount", but all other options are grayed out so I can't reformat if that's the suggested solution. Unmounting and remounting doesn't help.

I'm having trouble mounting 2 external 2bay hardware RAID drives. Formatted in disk utility, but then gone. For full description, see the following link:

Big Sur Thunderbolt 2 - External Drives-not recognized by multiple Macs.

Not sure if this is related. Interesting that my drives will mount just fine in USB, but not TB2.

"At some level of management you (Apple) made a trade-off decision to let this ride." Agreed. How awful Apple, shame on you. Jimbocal, Have you considered uninstalling Big Sur and going back to Catalina? I have not tried my backup HDs yet. But to update to my situation: Coincidentally, moments after posting an update posted today and I installed it. Suddenly! the computer recognized my External ODD device (Roofull) which I am using to read old CDs- Word documents. At least that is solved; now onward to check my storage drives. BTW the manufacturer of the ODD has given excellent support and I reported the BigSur issue to them.

Interesting. For others I had to find my "Locations" by clicking on "my macbook" icon. Will try this if I have problem another time. Still I do not think one should have to spend so much time on such a simple thing. Apple should fix it.

And so Apple finally (and secretly mind you) sent a patch overnight that automatically updated the patch. And after weeks of trying and almost giving up and sending it back to Best Buy, presto! It suddenly started recognizing the backup and every external hard drive. Once again, I didn't do anything differently, thinking I should just leave it for an hour or so and see if something happens, and yes it downloaded an external patch and updated the software. Now if Apple had listened to this community from the beginning and got the developers to update the patch, this whole thread would have never existed. As it stands lets hope that my 10 external HD's won't wear out and i lose all the info permanently from whatever is in the patch. Anyway thanks Apple, you saved me a FINAL trip to BESTBUY, and still continue to be a member of the community