Diskmanagement.disenter error 49218

I have the same problem. External SSD drive for Timemachine, APFS formatted. Creating the initial backup worked, then was running for some time and all of a sudden it can't be mounted anymore. Might be that it occurred after a reboot, I usually never reboot my Mac.

The same external drive was working before Monterey smoothly for over a year. After the update the Timemachine backup could not be finished because of some strange file conflict. Whatever, I reformatted everything and started from scratch and now I am in this new situation.

I think there is a sever bug somewhere in Monterey.

Same problem. External SSD for Time Machine, APFS formatted. Lost access with Monterey and can't get it back.

I did find this:

https://developer.apple.com/forums/thread/680500?answerId=676624022#676624022

Not formatted in ExFAT (APFS), but after entering command was prompted for password but had no ability to enter ($ sign was pre-entered.)

Same problem. Thanks a lot Mac Monterey. Now I can not access my files.

Same issue with my drives…. I had an external drive for my pictures and I could not access it. I tried saving it through terminal with all the commands i could think of…. Nothing really helped. In the end i capitulated and bought „Disk Drill“ to access my files.

Then i loaded all the pics on a new external drive and about two weeks later the same error happened. I am afraid, Monterey has a weird bug.

Exact scenario here too, running Catalina on an External SSD. Same error number too. External drive worked fine running Catalina for over a year using the motherboard of a late 2015 MacBookPro running Sierra (the "32 bit software issue"). Battery on laptop was changed in mid-December. When I tried to connect with External Lacie 1Tb upon laptop's return, external drive would not mount. Disk Utility repair and mount failed, running Catalina on yet another 5Tb external drive and Sierra OS on laptop. 1Tb External drive was running Logic ProX and Final Cut Pro. Raw files backed up, but changes currently unattainable. Feels like some sort of permissions denial? Dunno. Does Lacie place empty space cushions in their drives, so they don't fill to the brim? I wonder if I remove/delete contents in VM or Recovery partitions (related to Catalina OS install?), if it will free up space for drive to mount? Wondering why there were no "disk full warnings." I thought there was 8 Gb of space left when I took in the laptop to Apple for battery repair...

Just ran square into this issue today too. Brand new 8TB WD Elements drive formatted in APFS. Connected via USB 3 to a thunderbolt dock.

Error: Could not mount “Time Machine 8TB”. (com.apple.DiskManagement.disenter error 49218.)

Worked perfect as a Time Machine Disk for the last 31 days. Then abruptly stopped and will not mount.First Aid checks showed nothing wrong with the disk.

I'm running Big Sur 11.6.2 on a 16 inch 2019 MacBook Pro.

FIXED - NOW I'M GOING ***** 😁

Same issue here. Can`t mount my apfs timemachine since 4 days now. Worked almost a year without problems. Has anyone tried the 12.2 beta already and can still confirm this issue?

FIXED ... by doing WHAT? Please post a solution to this problem if you could fix it.

Same issue here with a 4 TB WD My Passport on Big Sur 11.6.2

I had this happen 4 TB WD My Passport on Big Sur 11.6.2, the 1 TB partition for my Time Machine didn't come up and mounting gave the "disenter error 49218". Here's what worked for me (at least for now):

https://developer.apple.com/forums/thread/680500?answerId=676624022#676624022 "Try to mount the disk, and switch to Terminal and write sudo pkill -f fsck"

Attempted to run First-Aid on that partition.

Restarted the computer.

Time machine came back after that. No clue which of the steps may have actually fixed it. Will find out the next time that this inevitably occurs.

This worked for me too:

https://developer.apple.com/forums/thread/680500?answerId=676624022#676624022%C2%A0%22Try to mount the disk, and switch to Terminal and write sudo pkill -f fsck" Attempted to run First-Aid on that partition. Restarted the computer.

I agree it's a weird bug with Monterey. I ran into the same issue with my external Samsung 4TB SSD. After I upgra ded to Monterey my drive immediately started acting weird and then I received this message "Could not mount “4TB SSD”. (com.apple.DiskManagement.disenter error 49218.)" I've tried all kinds of software including Terminal to force mount and I'm still unable to mount this external drive. I have over a decades worth of family photos in iPhoto on this drive most likely all lost. Thanks MacOS Monterey!

I unplugged a 1TB SSD without ejecting it first, and when I connected it again sometime later, I couldn't even see it in Finder.

I opened Disk Utility and run first aid on it and got an error (com.apple.DiskManagement.disenter error -119930878.) but after I closed it, it continued running and some minutes later, the drive was fixed and I was able to see it in Finder and use it again.

I'll remember to eject the drive properly next time before unplugging it.

I unplugged an external HDD without ejecting it first, then had error 49218 when trying to mount it. Surprisingly First Aid didn't show any errors, but still I couldn't mount it. Restarting the MacBook helped, it just automounted. I'm on Big Sur.

Restarting the MacBook worked

Ok, I had this same issue and found a fix. However, it's ONLY a fix if you do not care about what is on the external HDD. Open Disk Utility and hit Partition. Change it to APFS (Encrypted). I hit "Apply" and it warned me that all data would be deleted. I said ok. It wiped it and then it automatically mounted and all is well now.

Mine was previously on APFS (case sensitive) and I had all of the same issues you all have had and none of the suggested fixes did not work.

FIXED! I've had trouble accessing my external LaCie time machine drive for a while now and nothing I had found online has helped. Couldn't mount it, erase it or use first aid on it. Would get failed messages non stop. The only solution that has helped I have, fortunately, found was by this guy on youtube, https://www.youtube.com/watch?v=Z9y1oRYlmh0. Formatting the container within the disk utility to a MAC OS Journaled had worked and I was able to access the partition anew and then restart the time machine.

I am no developer, but was reading these forums and thought of posting this in order to, maybe, help some of you.

I'm having the same problem with my MacBook Pro M1 max. I have a 2TB external drive I was using with Time machine backups that I can No longer mount. Even disk utility won't allow the disk to be erased and reformatted. I would have thought that apple would have the solution by now seeing how so many have encountered this problem. can someone please help????

I've seen all the post on how to regain access to the disk, but how do I do that without erasing and loosing all my Time machine backups?

same problem: using a sandisk portable 1tb ssd on an m1 mac mini with big sur. i usually leave the external plugged in and let time machine do its thing. it started complaining about the external not being dismounted before disconnecting, but it was never disconnected. eventually it wouldn't mount at all. disk utility sees it, claims to repair it, but can't mount it.

Same Problem here, it happened after the MacOS firmware update to 12.4... I use an external WD hard drive, APFS (encrypted). Already conacted the Apple and WD support, they couldn't help me

I'm having the same issue...

I'm having the same issue. Is it something to do with the update?

I had the same issue - I plugged in the USB drive and one volume of three on the physical drive wouldn't mount, giving error 49218. MBP mid-2014 with Big Sur 11.6.8. Like some others, restarting my Mac (with the drive still attached - not sure this is relevant) brought them all back.