My exFat sandisk extreme driver get unmounted and cannot be mounted again

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My exFat sandisk extreme driver get unmounted and cannot be mounted again

Recently I'm encountering a weird problem.

My external exFat driver get unmounted and cannot be mounted anymore unless I plug it to a windows machine, get to run chkdsk on it, and plug it back on my mac. I'm then able to browse the drive for a while till it get unmounted again.

Trying to mount it manually on diskutils I get this error:

Could not mount “disk4s1”. (com.apple.DiskManagement.disenter error -119930868.)

Trying to run first aid on the partition I get this error :

Performing fsck_exfat -y -x /dev/rdisk4s1

Checking volume.

Checking main boot region.

The volume could not be verified completely.

File system check exit code is 1.

Restoring the original state found as unmounted.

File system verify or repair failed. : (-69845)

Trying to run firstAid on the disk I get this error:

Running First Aid on “SanDisk Extreme SSD Media” (disk4)

Fixing damaged partition map.

Couldn’t modify partition map. : (-69874)

Operation failed…

only solution is to go back to windows where the drives works properly and run a chkdsk if I want to get it recognized for a short while on mac os.

thank you for your help

MacBook Air 13″, macOS 12.0

Posted on Nov 28, 2021 12:52 PM

Reply

Answer 1

Nov 30, 2021 3:54 PM in response to jonnyac

Hi jonnyac,

You might want to try reformatting the entire drive as ExFAT on the Mac side, in Disk Utility. This should produce a valid partition table and filesystem that both macOS and Windows can use. Once the reformat is finished, you can repartition the drive if desired.

BACK UP YOUR DATA ON THE DRIVE BEFORE PROCEEDING. REFORMATTING ERASES ALL DATA.

Connect the drive to your Mac.
Open Disk Utility, located in Applications -> Utilities.
Select View -> Show All Devices.
Select the top level of the SSD and click Erase. Choose these options, then click Erase:
1. Name: Whatever you want
2. Format: ExFAT
3. Scheme: GUID Partition Table/Map**
When the erase is finished, quit Disk Utility and restore your data.

** If you plan on using the external drive with Windows PCs running Windows 7 or earlier, select Master Boot Record instead.

Reply

Answer 2

Jeff_W.

Community Specialist

Nov 29, 2021 10:36 AM in response to jonnyac

Hi jonnyac!

It sounds like your external hard drive is not mounting properly, and we're happy to help. To help us further assist you, please answer these questions: