Hi George.
Sorry, I cut and pasted the versions in the wrong place in my comment. Updated from 2304 to 2305 of course!!
The runtime errors have always been errors, they were just suppressed when the end user opened the application and now they are not for some reason. They were always flagged when I open the application in 'developer mode'.
I have two machines with the two different versions of access set up now and have been trying to investigate what might be different, but I have been through every single setting etc and nothing has visibly changed.
All I know, is that when I enable special keys on version 2304 I get runtime error notifications and when I disable them I do not.
But on version 2305 I get the runtime error notifications regardless of whether special keys are enabled or disabled.