An external disk refuses to mount, com.apple.DiskManagement.disenter error -119930868.

I had the same issue on Big Sur after turning of an external hard drive without ejecting first. I have an external hard drive with several partitions and only one was affected by the error com.apple.DiskManagement.disenter error -119930868

I opened disk utility selected the unmounted partition and ran First Aid on it. It took a few minutes and then I could press mount and it mounted it again just fine.

Hope this helps someone.

So it's day 187 since I my 12tb raid 5 array failed to mount. Today is the day that I was finally able to retrieve my data!!! I've momentarily stepped away from the strippers and the 5 kegger raging celebration that I'm having in order to write this post. So over the last few months I've tried everything that I've found in here as well as various other failed means and methods. I've tried a variety of terminal commands in different orders, leaving the computer and drive on for over a week. I even attempted some of the most ridiculous methods such as turning things on and off in a certain order. I've killed the .fsck process..tried the drive on multiple versions of OS X (I run dual boots and have old old Macs laying around, like Sierra, Yosemite old) hmm what else? I think that covers it although I may be forgetting a few things. So how did I do it you ask? Well I recently picked up a Qnap tvsx72xt box. This is NOT an advertisement and it was an accidental and very costly solution. So The box comes with it's own linux based qts4 operating system and you can hook up a keyboard, display and mouse to it or work it remotely over your network. You can plug drives directly into the box and offload them. So after migrating close to 60TB of media over the course of several weeks I was down to my unmountable 12tb raid 5 array. I plugged it in expecting nothing to happen and boom It shows up as an external mounted drive inside of the Qnap file station app. I'm able to pull all of the media from the once unmountable drive and ingest it into the Qnap box. An expensive and happy accident as far as a solution goes but yeah I got my stuff back. I'll still follow this post out of sheer curiosity as to how large it will grow and how much time will pass before apple acknowledges it. If it isn't fixed with Big Sur I doubt it ever will be. Just wanted to thank everyone for all of the information as well their unrelenting tenacity in search of a resolution for this issue. You can't f__k with people's ability to access their data and then just sit on your hands APPLE!!!!!!!!!!!

I am having the same issue/error code HOWEVER, I just recently updated my IOS to Big Sur to see if this would solve the issue and not only it isn't mounting, it is also corrupting my expensive Memory Cards! I am being as careful as possible but seems like it's just not mounting ANY of my cards and only a few smaller memory cards under 128GB seem to be able to mount after trying a few times. I am a photographer and the thought of images being lost is a total nightmare.... my current laggy fix is to use my Mark IV wi-fi feature to teadiously transfer them... HELP PLEASE!!!

Do You have an iPad/iPhone? Do you have or use Adobe Lightroom cloud ? You could get the SD to lightning card reader and ingest your photos that way. I do this when I’m away and wanna edit remotely. It works flawlessly. Lightroom cloud detects an external media source is connected. It will suck the photos right into LR and up them to your cloud. From there you could pull them down vis desktop.

I have this exact same issue, but this time after I installed "Big Sur" OSX update earlier today.

For ages I've had a 1TB external drive, partitioned into two parts, one part for use by Time Machine, the other part for use as Drag and Drop. The drag and drop partition mounts fine. After the Big Sur upgrade the Time Machine part will not mount and disk utility gives this error:

"com.apple.DiskManagement.disenter error 0."

It is now several hours since I did the upgrade. The Drag and Drop partition mounts fine, so it cannot be anything to do with the physical disk.

Is the Time Machine part doing some kind of housekeeping? It seems to be rumbling a bit from time to time, and it rumbles when I try to mount it via DIsk Utility, but then it gives the error message: "com.apple.DiskManagement.disenter error 0."

I understand that I could reformat the disk to get Big Sur to work on it better. But I cannot do anything if it doesn't mount.

Should I just wait?

Just had the same problem when updating to Catalina 10.15.7 (19H114). Tried killing the fsck_exfat in my case and that gave me an error message saying Can't repair my drive and I can still read and save but not save while open a file. I think it's still the same issue, when updating it triggers the fsck. Anyone from apple on this?

Hi everyone!! I believe I solved this problem (after trying literally everything in this thread). I was transferred from Apple support person to apple support person but finally one of them went to Apple engineering and figured it out.

It might be different for you guys and it's an excruciating process. But first, we went into go > library > launch agents and then isolated every single file (put it into a new folder, restarted, tried mounting) and nothing was fixed.

Then we went into launchdaemons and isolated every file in it again. It turns out for me, it was coming from an Application my company installed called DGAgent or something and we suspect it wasn't updated for Catalina and Big Sur. The file was called "com.verdasys.dgagent.plist". I uninstalled the software and made sure this file wasn't in the LaunchDaemons folder anymore and my issue was solved.

I believe the issue for everyone is probably coming from one of the files in these two folders.

I have an external drive with one data partition and one Time Machine partition. Worked fine until December, then I could not mount either of them with this error. I can mount them on another MBP running Big Sur. I also upgraded this MBP to Big Sur and was able to mount them, but had to downgrade back to Catalina for other software incompatibilities, and now I cannot mount the Time Machine disk again. Sigh.

I have the same issue. I've tried everything listed here and nothing worked.

The only thing I could do would be to erase everything and loose all my data.

My last option will be to try to see if it work on another computer in the house. Do a back up of the file on another HD and reformat everything. Very annoying !

I have 3 different external drives 2 Seagate and 1 Western Digital. My macbook pro keeps disconnecting them for some reason and they don't eject properly. I was able to get all 3 working again by simply rebooting the mac and waiting. Not really sure how long it took, but it did reconnect by the end of 3 hours.

If you can't wait, you can always connect through a windows box OR through a network router that has an external disk attachment. This process has worked every time for me and I use only ExFat formats for my disks.

Hth :-)

FYI - My disk got erroneously ejected again and this time I watched how long it took to become available after reboot. It took roughly 40 minutes for a 4TB Seagate disk to be mounted on my 2019 16" MacBookPro.

SOLUTION: Same thing happened with my drive. I plugged it into a Windows machine and ran a repair on it which I was able to do, unlike on a Mac it did not want to do anything at all. After it scanned and repaired it, I plugged it back into my mac and it is now working. Good luck.

sound stupid... but make sure you are not in safety mode.

.... i had a slim external cd rom sitting on my macbook and it was actually holding shift down so when i restarted it was in safety mode... external drive would not mount.... there was also a more prominent outline around the dock. (catalina)

I am really very grateful to you, you have helped me save a very valuable information about my work and personal projects. I do not know how to thank you. Greetings from Mexico, blessings and good vibes.

There may be some process running in the background that hinders the MacBook to mount the disk, for me it was NTFS for Mac application so go through the Activity Monitor and quit unnecessary applications.