Disk image couldn't be opened. Resource busy.

[mattone]

Hi.
Using SD, I made a clone of an external hard drive (startup disk clone) to a sparse disk image on another external drive. I let it run overnight since it wasn't done when I was going to bed (~600GB). This morning I check the spare image to see if I can open it. Double-clicking brings up a small warning modal window, "The following disk images couldn't be opened." Below it lists my new sparse image with the reason, "Resource Busy." [Okay] (button).

I checked the logs but I can't find anything about the backup I made last night.

Mojave 10.14.6
Both USB disks are HFS+ journaled
SuperDuper 3.3.1 v121

Please advise.

Thank you,
Matt

[dnanian]

Did you try restarting your Mac? This kind of message sometimes comes up when the image isn't fully unmounted, or there's a stray mount point in /Volumes.

(It can also come up with the host volume is busy somehow.)

[mattone]

I have not tried restarting. I did read about trying a restart in this forum but it was an old-ish post. I was hoping for another solution. I'll try a restart and try to mount the spare image. If that doesn't work, would you recommend re-doing the clone copy?

[mattone]

Restarting did the trick! Thanks Dave.

[dnanian]

Amazing what a Windows-like solution can do. :-) (Glad you're all set.)