Com.apple.DiskManagement.disenter error 49218 usually occurs when you're trying to mount or repair an unmountable external drive on Mac. It could be caused by various issues, such as temporary system glitches, fsck holding your drive hostage, file system corruption, macOS bugs, etc.
I recommend you try a reboot with your hard drive connected first. If your drive is still not mounted afterward, try mounting it from Terminal.
I see that you've attempted to mount your drive with the command: mount /dev/disk3, but it's not the correct way to do it. Instead, you should run the following command (if disk3 is your external drive's identifier):
diskutil mountDisk /dev/disk3
If it doesn't work, try the following steps to resolve com.apple.DiskManagement.disenter error 49218 on your APFS external hard drive:
- Open Disk Utility.
- Select your external hard drive and click the Mount button again.
- In Terminal, run the command below to kill the fsck process.sudo pkill -f fsck
- Type your administrator password and press Enter. (The password won't echo to your screen.)
- Check if your drive is mounted.
- If not, select it and click First Aid to repair it.
- Restart your mac.
Suppose your drive still won't mount, then you should consider reformatting it after retrieving the inaccessible data. You can download iBoysoft Data Recovery for Mac to recover data on the unmountable external hard drive. It can restore data from all types of internal and external storage devices, such as SD cards, USB sticks, SSDs, HDDs, etc.
It's compatible with macOS 13 Ventura ~ Mac OS X 10.11 El Capitan running on Intel and Apple Silicon Macs. So it should work perfectly with your external hard drive and Mac. Click the button below to install it and preview files on the unmountable drive for free.
After your data is restored, you can reformat your external hard drive on Mac to eliminate com.apple.DiskManagement.disenter error 49218.