OK, I am going to try again.
Closed QU (it would not close, gave all kinds of errors, including I/O error, in the end I had to kill it via the task manager).
Rebooted my PC to give it a fresh start.
Launched QU (it shows the message to watch training videos, probably due to inappropriate shut-down).
QU lost some settings, had to reconfigure a couple of things, apparently it does not like to be killed
![Cool](https://ddisoftware.com/tech/Smileys/default/Cool1.gif)
Started the print job from scratch: dropped an image from my DAM in QU, selected the 120 x 120 mm box
Right clicked the Properties button, select sRGB color space, click OK
Switch to Imperial via Edit > Preferences > Units
Hit the Printer icon, send the file named 'test' to the desktop and it goes without generating an error message.
![Huh?](https://ddisoftware.com/tech/Smileys/default/Huh1.gif)
Poor Mike, intermittent errors are the worst......