old Mac problems: Disk image failed to mount: Device not configured

Run /Applications/Utilities/Disk Utility.Click on “Macintosh HD” in the left column and then press the “Repair Disk Permissions” button.

Delete the file called /System/Library/Extension.kextcache

Delete the folder called /System/Library/Caches/com.apple.kernalcaches/

Restart

After these steps, disk images mounts properly

via Disk image failed to mount: Device not configured.