Diskmanagement.disenter error 49218

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.

Hi everyone, Today I was surprised by my MacBook with the same problem. I have the 4TB Sandisk Extreme on USB-C and I got this error. Tried a few things and by the time I have decided to give up and getting ready to delete the messed up partition and format my drive, I decided to give it a try on my iPad Pro Gen 4. Guess what. iOS can read the partition and right now I am in the process of copying everything of the Sandisk.

This is what works for me. I can see all the files and I am more than half way with copying.

Have a good day.

Uncle E

I've had the same exact issue as everyone posting here. M1 Macbook pro connecting to a 1TB buspowered SSD with the error (com.apple.DiskManagement.disenter error 49218.) Very frustrating to say the least and makes me extremely leery of trusting APFS at all going forward. I'm in need of fixing this drive and using it this week but thankfully my drive in question has been backed up elsewhere so I'm afraid my only solution is to start over and use anything else besides APFS. 😔 Apple, please fix this terrible mishap!

I did however want to give any frustrated users some hope for their data:

Plugging my drive into an iPad does reveal all of the contents on the drive. Don't understand why at all but it's at least a way to help see what's on the drive. Thanks to Uncle E for that option!

And for any of those wanting to recover via "Disk Drill" or other recovery software, Setapp is a cheap subscription that gets you access to Disk Drill and many other apps. There's a free trial so you can grab all of that precious data: https://go.setapp.com/invite/mffb1pna

Hope that a fix happens someday and it's on Apple's radar 🙏

I am having the same issue since I upgraded my computer to Monterey 12.5.1 I can no longer view my newest western digital hard drive on my MacBook Pro anymore. I have a passport 5TB drive and it is no longer mounting on my Mac.

I'm seeing this with Big Sur 11.6.8 So far I've found that it happens consistently with two external USB spinning disks used for the Time Machine. Often one of the two will mount, Time Machine runs fine.

This happens to my macbook pro after using an external monitor/mouse. (External keyboard is bluetooth) After disconnecting the monitor/keyboard/mouse, sometimes one of the two external drives will work, if I plug it into a USB port that was NOT used for the monitor/mouse.

Consistently, both external disks work after a laptop power-off/on, continue to work with multiple unmount/disconnect cycles. The first time I use the external monitor/mouse, then disconnect them, plugin the external disks, one or both disk will not mount.

This looks like a bug in how the USB ports are reset after use.

Apple support recommended updating the operating system, a good answer. However, reading through all of these replies, it really looks like a kernel or driver use case bug.

Same for me. I have now three irrepairable APFS disks lying around waiting for the engineers getting their act together. That is more trashed disks in 5 years of APFS than in the 25 years or so that HFS+ is around. HFS+ was always salvagable somehow if there was a problem. APFS? not so much. What a poor performance on Apple's part.