Big Sur - external discs not mounting

Same thing, but I didn't upgrade. I'm using a fresh M1 Macbook Air and it simply won't mount anything external. I can see it. It just says "not mounted"...

Same thing for me. I can plug it into my iPad without any issue, so it is definitely not a problem with the HDD. It seems like it may be a bug on 11.0.1

I have the same issue. External USB drive's that still mount in Catalina don't mount in already-running Big Sur. But if they're plugged in when Big Sur starts up, they'll mount OK.

Well, please disregard my post of a few hours ago. I shut down, started up, and now external USB drives are mounting fine. Beats me. Sorry if I'm in anyway out of line ... I'm new here so thanks in advance for slack.

I have similar issues with external USB Flash drives on Big Sur 11.0.1 (MacBook Pro (Retina, 15-inch, Mid 2015)). After plugging in USB drive I can't find it in Finder but it still can be founded under /Volumes folder. Open Finder -> Go -> Go to folder /Volumes (shortcut SHIFT + CMD + G). I hope it'll help.

Similar issue here too. When plugging in either usbC or usb3 external drives - my experience shows this is a flip of the coin whether Big Sur recognizes and mounts the drive or not. I think particularly that the exFAT partition format type has something to do with this issue. Apple's Disk Utility also has a hard time displaying what the actual formatted partition is. For instance, I took an Apple drive over to my Ubuntu Linux machine, erased the drive and repartitioned it as exFAT, removed it and plugged it into my MacBook Pro on a USB adapter and it didn't recognize the disk even after several unplugging and replugging attempts. So I rebooted. It saw the external drive, but showed it still as an Apple Journaled APFS partioned drive. That's odd I thought, so I unmounted it, removed it and plugged it back into my Ubuntu Linux machine. Lo and behold it was exFAT not APFS. What's going on with Apple's Big Sur? Hard to say, but it looks and feels like a bug.

I'm having this same issue with my Macbook Pro (2019). I've tired restarting. I've tried repairing disk but it will not mount. I'm not sure what the cause is. I have my music library on it so I don't want to format it and lose it. It's currently in Fat32. I'm unsure why Big Sur won't read it as my computer was able to read it on Catalina when I first got it.

I Have similar issue, i can see my external drives but if i transfer files to or from the external drive it starts slow and stops and in some inctents iit exit it by it self. i started seeing this after the update 11.1- Please help.

I'm also seeing this issue on an M1 MBP. I'm able to go into Disk Utility and mount my external drives from there, and I'm prompted to enter my drives encryption password. And regardless of whether I check the box to remember or not, it doesn't remember and mount them again after a reboot. Not sure of the cause here, but I'm (in my head anyway) attributing my slow Finder beachball issues to whatever is causing this issue.

I have a MacBook Pro 2019, My seagate 1TB hard drive would not mount for a while..... I have a thunderbolt -usb adaptor connected and thought it might have originally been a poor connection due to cable, after restarting my Mac in safe mode and restarting etc etc nothing appeared to work. but after leaving the device connected for approx 20mins the hard drive and all its files have appeared. just thought id share this anyway.

Macbook Pro, M1, Big Sur. Attempted to transfer file from win10 pc to mac via flash drive. Flash drive mounted but files not visible, running properties indicated files were present. Inserted other flash drives from pc, the drive mounted but files not visible.

Hi There,

I was having the same issue with my external lacie G drive not mounting but was visible in Disk utility.

I tried all sorts of things and the one that worked for me was to zap the P Ram.

I am on MacBook Pro, so restart the Mac hold shift+control+option+power button 10 secs. Once I had done this I logged back in and boom the drive mounted. I hope this helps.

I have been having the same problems not just with big sur but with Catalina also I have lost a lot of important work and file and more than one flash drive which has cost me a lot.
but what is bothering me is how Apple have not said anything, they keep bringing out new versions before making sure they are fit for use.
they need to work on the issues that are happening before moving forward.
i have spend thousands on there Products only for them to let me down and cost me more.
this is a joke.
Apple are proving to be unreliable.

I have same problems with new MacBook pro 16'. No HDD nor SSD. They worked totally fine with old MB pro 13' with Catalina.

in order to get big sur to recognize your USB drive & show it on the desktop

• Open Disk Utility

• Choose "Show All Devices" from the View menu

• Select the destination drive hardware (above the existing volume)

• Click Erase

• Choose the "GUID" partition scheme (2nd pop-up), THEN "APFS" formatting (1st pop-up) and name appropriately

• Click Erase

if you have files on the USB drive you should be able to open them with an app & then save them, if they are essential, before you erase.