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

You've not lost your data if you have a backup strategy in place, like Time Machine. Also the install process may have put a strain on the HDD portion of the Fusion drive during formatting and installing. It didn't happen to me but then, I didn't have a Fusion drive. I don't remember if most of the occurrences of this type of problem were Fusion drive related but maybe. In any case it's not good but with a backup strategy in place you won't lose any data.

Since this happened to me using a 5T external WD HD after upgrading to Catalina, here's what I've been experiencing. I've found if I leave the HD attached but not tended to (no activity, photo editing, etc) for a long period of time then I cannot easily eject the HD. I literally have to shut my MacBook Pro down, unplug it, and then restart the computer. When I plug the external HD back in, it does not mount right away but it will after say after 15-20 minutes. Then it works just fine. It's very annoying but I've not found a simple solution to all of this. One thing I make sure to do is use the WD utility and check the drive to be sure there are no issues when I replug the HD.

I tried the various things listed in the first couple of pages of this thread, including using Terminal to run the various commands suggested and nothing work. Also installed the Tuxera app, but nothing worked. Killing the fsck process in Activity Monitor finally did the trick for me. (Maybe the other things I did were necessary for that to work?) Yea! I am copying all my data to a new drive while I have the chance.

This is about the 3rd time I've had this issue with portable external drives, every time it seems to be a little different trick to fix it. The main problem seems to be that when typing on my lap, the cable sometimes comes loose and the drive disconnects. After this happens a number of times the drive fails even though I periodically have run the repair utility. I figure it is just the weakness of using these small, portable drives.

So I solved this by installing Tuxera NTFS. It allows your mac to read and write to NTFS devices and disks. My disk was showing up on disk utility but not on finder. Once I installed and allowed kernel access - the drive showed up and I could do my backup.

Hope that helps!

https://www.tuxera.com/products/tuxera-ntfs-for-mac/

I have many important files in the error hard disk, so I try to use another mobile hard disk to restore data from the error hard disk. When I clicked the restore from Disk Utility, the error hard disk is OK. And now my Mac is booting. FK APPLE

Same problem! New WD 4TB install but didn't mount. After MUCH forum review(s) I saw a link to a WD support page that WORKED for me as I want to use this drive as a Time Machine backup. I have High Sierra (10.13.6). It is important, apparently, to use the Mac OS Extended (Journaled) choice to erase/reformat the drive but within about 3 minutes I had a fully functioning Time Machine that is now backing up my iMac. Hopefully this solves your problems, too! Good luck.

https://support-en.wd.com/app/answers/detail/a_id/8200

Thank you for all your helpful comments. After two hours of wasted time, I found this forum. I tried Tuxera and it did not work for me but killing the fsck_* in activity monitor has seemed to work for now. This is ridiculous and should be addressed by Apple.

thank You @Torgash. Your response helped resolve this problem for me. I too ejected an external disk improperly, and was having trouble getting it to mount (on Catalina OS). I had tried several reboots, unplugs, disk utility mounts, but none worked. Then I read @torgash’s response and decided to give it “some time.” I walked away for about 5 minutes and walked back to find the external disk mounted and running properly. It seems in this case, it may be worth giving it some time......

Hello, You sent your thanks to the wrong person by accident. I am not @torgash, I am camionneur88. I did post a solution to this problem as well which is different from @torgash's. I am glad you resolved your issue. I received this error from a different reason (creating a ubuntu boot disk). Working through the offered solutions on this subject it seems that any number of things may cause this problem. Have a nice day & stay well.

Hola. A mí me sucedía lo mismo y lo que hice, siguiendo los consejos de un compañero de este fórum fue instalar la app TUXERA.

Tras dicha instalación, y después de reiniciar el equipo, el disco externo montó sin problemas.

I am trying to mount a micro SD for my Go Pro. If I format it using the Camera it will not mount. If I format using disk utility it will not work in the Camera I get an error code (com.apple.DiskManagement.disenter error 49223.) I am currently running Catalina

An external disk refuses to mount, com.apple.DiskManagement.disenter error - 0

I just cold-cut turkey pull the USB chord after many failed tries to mount unsuccessfully and when I plugged it back in it worked and I was able to retrieve all my data, IT WORKED!

I am running a MacMini with Catalina (current rev) and got the same error. I have an external Drobo Mini which has been working without any issues for years. But with Catalina I got this error. I ran "First Aid" (Disk Utility) without success. After that there was no indication of any disk I/O going on with the DroboMini...but 5 minutes later it spontaneously mounted itself and is good for both read and write. I have no idea what was going on in the background that caused the disk to finally mount, but I do know that I had nothing to do with it...not the result of any action I took. So the MacMini/Catalina combo seems to have a "mind of its own" and does what it will do without telling the user/owner/admin person that anything is going on. Glad it's working though I do not understand the idiosyncrasies of the process that got it working.

Your problem is related to a previously disk ejection not done properly. The disk does not mount because Disk Check is in progress, you should see fsck process in the Activity Monitor app. Unfortunately MacOS does not tell you about any progress so you try many times to plugin / out your disk.

Unfortunately my problem above is different (left the whole night and there is no disk check in background), but found software that should recover files. Its a shame that third party sw can fix this and Apple does not help in fixing APFS issue.

Thanks!!!! I have the same issue and this worked for me. After force quitting fsck_ext from the activity monitor my disk mounted with the message that I can read but no longer write to the disk. Now I think I can back it up :)