External Hard Drive Missing After Big Sur Download

I had the same problem, once I opened finder I was able to use the "Go" drop down at the top off the screen and select "computer" to find the SD card that I had plugged into my laptop. Hope this helps!

Thanks much. I will refer to this if it happens again. My thought however is "why should we have to jump through hoops and spend our time on this?" Period. For me it's unacceptable for such a high end product. Meanwhile perhaps there is a thread on the pros and cons of keeping this "upgrade"?

I am having the same issue with my 5TB WD Easystore HDD. Stoped doing back-ups and then I noticed it will not mount. I tried the power thing, mounting from terminal, etc...I can not even erase it to start from new. What the heck is going on? I remember when Apple products just worked. Please help

I had the same problem, once I opened finder I was able to use the "Go" drop down at the top off the screen and select "computer" to find the SD card that I had plugged into my laptop. Hope this helps!

I feel for you. These problems seem weirdly random? There are other suggestions in this thread, so read back. The last BigSur upgrade solved my problem with an external CD reader, however I have not yet checked my HD backup. I am still considering removing Big Sur and going back to Catalina.

Thanks for the response. I have tried everything. I can't even erase it. I dowloaded the latest software from WD, changed cables, etc....My Samsung external works fine on the same computer?? Makes no sense to me.

Love that when you go to reply, the dialogue box opens with "Tell us what's on your mind."

What's on my mind is it is pretty obvious this is a widespread problem that only began with the release of Big Sur. This thread goes back to the release of it. It's not something that just arose over the last two weeks.

It's spread across a wide variety of machines and many, many different HDs of all different capacities made by many different manufacturers. It so clearly is a Big Sur caused problem. I just don't understand why Apple's MacOS group is non-responsive.

The number of people expressing they have the problem just keeps getting bigger and bigger.

Come on Apple. Help us. Let us know you are listening.

So sorry. Have you called Apple tech support? Do they still work since Covid? Have you thought of uninstalling BigSur? What are the advantages of BigSur that justify the time/cost/benefit? I'd better find my HD.

UPDATE. I erased the HDD on Windows. Plugged into my MacBook Pro 16" 2019 and it recognized the empty HDD. I renamed the drive and picked it in Time Machine preferences and it started the first back up. This still sucks because it will take all day to do. We should not have to do these things for our products to work. I knew I had all my back ups from Feb 12 and prior before I erased the drive so I had nothing to lose. Proceed with caution if you try this. I will update this once my first back up is finished.

I had a similar problem. Though the upgrade to Big Sur failed so did my two external hard drives. Apple says that it is not thri fault and that I have to go privately to a Data Recovery Company which is very expensive.

Hmm my 1TB drive mysteriously died too. Tough it is 11 years old i still think there was life in it. I amable to plug it into a mac with high sierra and slowly get data off it before it bombs out completely. I have a second 500G drive that connects fine.

Time to go to the cloud with my photos.

So sorry for this major and inconvenient hassle. Are your HD failing to mount or did they get erased? Were they plugged in when you loaded the upgrade? How did they get erased? Hearing this is about the last straw for me. What is wrong with Apple? the known issues with BigSur are noted daily, a different one every other week. I think I will definitely go back to Catalina.

This thread originally started with drives failing to mount and various work arounds. As it progressed, some people posted Big Sur was responsible for their content being erased from their drives.

While they have Big Sur in common they are two separate issues and I wish they had not been blended into this one thread. While I have compassion for anyone who data was erased, I do not believe they are linked and have to think if they got erased something specific, but unintentional was done by users that caused this.

While the failure to mount issue has been widespread and posted and discussed on many different Mac sites, spontaneous erasure has not and I am not able to turn up much about it floating around the web. To me, it confirms these are not linked problems.

Apple's non responsiveness to the mounting issue is what is frustrating. No acknowledgment of any kind despite multiple threads on apple discussion boards. We know they listen and watch these boards. How about it Apple?

Perhaps you could be more specific about what you mean when you say they failed. I have trouble understanding how Big Sur could cause a failure that only data recovery services could fix. Was there a mechanical failure? Are they HDD or SSD drives?

Nope. I downloaded WD Drive Utilities app and was able to access the drive from there. The problem started immediately after upgrading to Big Sur - not a coincidence. Now that it's working, however I am able to access it, I can use Time Machine again.