Big Sur - External disc not mounting

I went apple support and searched for resetting SMC and PRAM. Their instructions are better than what I would type.

https://support.apple.com/en-us/HT201295

https://support.apple.com/en-us/HT204063

I was having a similar problem when I first plugged my new external disc drive into my macbook pro, which was recently updated to Big Sur. I finally decided to try attaching the drive through my Andobil usb-c hub. Though this should be unnecessary since the external drive is already type c, it worked beautifully. Hope that works for someone else as well.

It turns out my problem has been solved by resetting SMC and PRAM/NVRAM. A diagnostic program that I have used for years may have been modifiying registers. After removing that program and doing the reset the issue has not returned for long enough that I think the issue is resolved.

I had the same problem, and accidentally discovered a solution that is working. In Finder Preferences, under Show These Items on the Desktop, uncheck everything except Hard Disks. Then reboot, and then open Finder Pref and check the other items.

Great Success!!!!

Try the following: How to reset the SMC of your Mac - Apple Support

I had the same problem. I installed a driver from here and the issue got resolved.

https://iboysoft.com/ntfs-for-mac/wd-ntfs-driver-for-mac.html

Although, now my external hard is read-only, but I guess there is a solution for that too.

Simply open the Disk Utility App > Click the volume in question > in the upper right hand corner of the app window click "Mount".

This action will mount the disk in question manually, not resolution for the disk automatically mounting, but will provide you GUI access.

Thank you so much this finally worked I just changed the disk number and I needed to mount a NTFS disk so I changed exfat to ntfs.

This is what I used in Terminal: sudo mkdir /Volumes/External/ && sudo mount -t ntfs /dev/disk2s4 /Volumes/External/

Just change the disk2s4 to whatever disk you want to mount Ex. disk2s1, disk2, and etc.

I used paragon NTFS previous to Big Sur, but did not work after updating to Big Sur.

I since moved to Tuxera NTFS, and is briliant. 

First make sure the Finder's General preference pane has all checkboxes checked.

Next, if necessary do the following: How to reset the SMC of your Mac - Apple Support

you can try this on your Terminal.

Ex-Fat : sudo mkdir /Volumes/External/ && sudo mount -t exfat /dev/disk2s1 /Volumes/External/

Fat32: sudo mkdir /Volumes/External/ && sudo mount -t msdos '/dev/disk2s1' /Volumes/External/

https://discussions.apple.com/thread/252053844?answerId=254850114022#254850114022

I have the same problem? Can you see it in your system information panel ?

I do :

Product ID:	0x1093
  Vendor ID:	0x059f  (LaCie)
  Version:	1.00
  Serial Number:	XXXX
  Speed:	Up to 5 Gb/s
  Manufacturer:	LaCie
  Location ID:	0x01100000 / 3
  Current Available (mA):	900
  Current Required (mA):	896
  Extra Operating Current (mA):	0
  Media:
Rugged USB-C:
  Capacity:	5 TB (5,000,981,078,016 bytes)
  Removable Media:	No
  BSD Name:	disk2
  Logical Unit:	0
  Partition Map Type:	GPT (GUID Partition Table)
  S.M.A.R.T. status:	Verified
  USB Interface:	0
  Volumes:
EFI:
  Capacity:	209.7 MB (209,715,200 bytes)
  File System:	MS-DOS FAT32
  BSD Name:	disk2s1
  Content:	EFI
  Volume UUID:	0E2XXXX
LaCie:
  Capacity:	5 TB (5,000,770,093,056 bytes)
  File System:	ExFAT
  BSD Name:	disk2s2
  Content:	Microsoft Basic Data
  Volume UUID:	EXXXX

Trying

% sudo fsck_exfat -q /dev/rdisk2s2
fsck_exfat: Can't open /dev/rdisk2s2: Resource busy

So the drive seems to be hanging....

This is a major issue. Apple must fix this. So far the only thing I have found to work is unplugging the external disks then plugging them in again. That is not acceptable. Apple get your act together.

sudo mkdir /Volumes/External/ && sudo mount -t exfat /dev/disk2s1 /Volumes/External/

or

sudo mkdir /Volumes/External/ && sudo mount -t msdos '/dev/disk2s1' /Volumes/External/

Tried this ^ ??