I cannot tell from the message whether this was a crash or a timeout ("Not Responding" in caption) followed by an attempt to close the application which did not succeed and made Windows think that the application was hung.
If it is a crash and you see it again, please capture a crash dump. (Crashes are good in this respect - a captured crash dump almost always immediately shows us what exactly went wrong, and you don't have to remember anything or send us any data, just the dump file.)
Copying from an earlier post:
Capturing a crash dump is pretty simple. Suppose you are working with Manifold and it crashes. You see a scary error message. *Without dismissing the message*, launch Task Manager, locate the Manifold process in the list of processes (in Windows 10, the list of processes is in the Details tab of Task Manager), then right-click the process and select Create Dump File. The system will take a moment to write the dump file and tell you where it put it. Zip it up and send it to us.
Thanks a lot for the report.