External Hard Drive Missing After Big Sur Download

(SOLVED - At least for me)

I have an external SSD that stopped mounting. I could see it in Disk Utility but I couldn't get the actual volume to mount so I started searching around to find a fix.

• Disk Utility would not repair it. Any first aid or repair would keep failing.

• I then tried booting the OS in single-user mode as some suggestions but this wouldn't work for me. Apparently, you're supposed to hold Command+S at boot but this never worked for me. Did Apple change something with Big Sur that prevents this?

• I then tried booting in safe mode, but that also didn't work on my machine. Thinking the issue is the OS, I tried mounting the drive on an older laptop.

• On the older laptop I had the same problem. I could see the disk in Disk Utility but I couldn't mount the volume. Also first and repair kept failing.

• So finally I try one more thing:

SOLUTION:

> Plug the drive into my mac (Big Sur M1 Mac Mini)

> Open Disk Utility

> Run "First Aid"

> First Aid Fails

> Open Activity Monitor

> Search "fsck"

> Force Quit "fsck_hfs"

> Switch back to Disk Utility

> Run First Aid again

> First aid works this time and disk mounts

The repair is still running and the disk is really sluggish but hopefully, this allows me to get the files offloaded to another drive.

Not a solution, this is done by design, AFPS is apple's own file structure system...Recovery developers like Diskwarrior stated that Apple is not sharing codes with them so they can not recover Catalina or Bigsur drives, only Carbon Copy Cloner can since that developer worked foe Apple once, the rest offering help are online services requiring users to upload their hard drive to the World Wide Web and so dont count on this to be 100% private.

The idea that EFI firmware is quietly dropped during Catalina or Big Sur updates is absurd,

During a number of updates I lost access to internal drives and recovered them by using the latest system on devices apple supports, all which happen to be AFPS drives,

-I used an iPad Pro to see if I can get a drive I lost access to via Catalina and it worked, it was all EFI issues with an older MacBook Pro.

You may allege this is forced obsoletion, extortion etc but until there is a logical explanation and evidence your either going to spend ages trying to get a 3+ year older Mac working normally or buy a new one.

The solution is not to update or upgrade if you plan on using an older machine,

The risk of security is a problem when your on older machines, you need 3rd party software for more help but its possible.

How I wish i'd researched about Big Sur first before finally updating yesterday. I thought everything is okay by now since this has been available last year. Same issue here, I cannot see my external drive, instead I can only see an external drive named "Update". Because of this, and other issues on email, photos, missing folders and very slow speed, I reverted back to Catalina via Startup Disk (Catalina on Macintosh HD vs Big Sur on "Update").

Like the others here, in the Disk Utility, I was able to see my originally named external HD "Touro MacBook BU". I used First Aid for the external HD but I still couldn't see it on Finder.

Here is the workaround I did to access my external HD files:

> in Disk Utility, right click on your external drive ("update" will be there too) and select Show in Finder.

> a Finder window will open your external drive and show folders App, boot, Lib, Sys, Users.

> unhide hidden folders by pressing "command shift dot"

> you will find a hidden folder named Volume, you should be able to see your Data folder in there containing your files.

This is such a hassle because you can only access your External HD via the Disk Utility :( it is the only place where I was able to see it. I hope "Big Sur" acknowledges this issue and finally provides a fix.

I also have apps and software that no longer work the way they did before. And my machine is very slow. I cannot possibly afford to buy a new machine. Question. How did you go back to Catalina without losing data? I do not have a recent backup from before I let apple sell me on “upgrading”. For now I have been putting up with the dread beach all and all the other things that no longer function as before but I’d prefer to go back to Catalina. What are my risks??

Was this problem ever resolved? I'm here six months later after finally doing an upgrade - which I was avoiding for this same reason! Now, I can't access my drives for a huge project. This is madness. How can things like this still happen? I see no resolution below. Two of my drives will not mount.

If you have to get another external HD seriously consider one from OWC (MacSales.com):

Envoy Pro EX with USB-C or USB 3 - best from a speed vs price standpoint

OWC Envoy Pro EX with Thunderbolt 3 - fastest if you have a Thunderbolt 3 port but more expensive

 OWC Mercury Elite Pro 7200 RPM Storage  - excellent choice for Time Machine use.

Yes, madness. Personally, I would not have gone to Big Sur if I had read this thread ahead of time! Which problem? Specifically most of this thread is about not being able to see external drives. There are 14 pgs here, so depending on your exact problem there may be a work around, not what I would call a fix. Did you assume it had been resolved? Hope springs eternal, but there are many comments here about Apple just not being the same responsive company it used to be. But many people seem to have no problem at all and like it. My suggestion: take some time and read the entire thread - you might find an answer. Apple so far has not furnished one.

Thank you for your reply. I did not find an answer in the forum. However, I did solve the problem by calling an Apple repair shop (not officially Apple BTW). Here's what worked for me...Do a youtube search on how to perform a pram and smc reset. Both are absurdly simple and only take minutes. That instantly allow one drive to mount. Then, I had a pop up warning about NTFS for mac. I clicked on that and a previously undiscovered window appeared that allowed me to mount the remaining problem drive. It's amazing that this update has been out for SIX months and Apple has not issued a fix. They love appearance of being user-friendly but when problems happen, they just aren't there. I hope this fix will work for others.

Hey Rockingdee, I am facing a similar problem and was just checking in to see if you have found the solution.

I have a 5TB Seagate Portable Backup Plus which was running fine till I updated my Air to Big Sur. It was ExFat formatted. It shows up on Windows and even my older Mac.

I took a backup of the disk and reformatted it. But no luck. I even formatted it to APFS, but it's still not showing up. Even in Disk Utility.

Funny thing is that my WD 1TB external hard drive works. So I don't know whose fault it is, Seagate's or Apple's.

If you have a solution please let me know. (I have tried downloading Microsoft NTFS, Tuxera too. No Luck)

Thanks!

I’ve had nothing but problems with external hard drives since “ upgrading” to Big Sur.

ive lost countless terabytes of data. Reformatted drives etc.

what’s the deal?

I have 4 4tb external drives.

I WANT A FIX!!!!!

Sevenfish wrote:

Yes. I have more than a rant.

what are you going to do to fix the problem?

I'm not going to do anything. We're all users like yourself here so can only ask for into and try to give help based on what we've experienced ourselves and seen here. So what are you going to do.

I have ALSO been having Drive and disk issues. This new bigSur MacOS is not as great as previous builds. Some things are nice and cool about it, others are absolutely terrible, like the finder window and toolbar space.... But back to the drives.... Mac OS Big Sur will trip on my external ExFat drives most notably after they are mounted on my windows 10 pc. I could also tie the issue to windows except that my older macbook running high sierra does not present those issues. Can you guys Downgrade/upgrade diskutil, and disk utility to that of older versions of Mac OS when First Aid actually fixed something, or gave us more controls to fix drives, permissions and etc?

Update: I was able to get the drive to property detect again. I had to fully reset my SMC (followed steps here: https://support.apple.com/en-us/HT201295) then it was properly detected at next boot.

How is the external HD formatted?

Hi Old Toad, thanks for your help!

Format seems to be "Mac OS Extended", here a screen capture: