What is this Runtime Error?

Can anyone tell me what this is?

Runtime Error Common\\ObjectModel\\RuntimeObjectFoundation.cpp: 1017 Failure Condition: target

This happens only in the built application on Windows. DebugBuild shows no error.

an assert() in C where some condition is not met.
e.g. target is a variable name and it is nil, but should not be nil there.

Thank you. Unfortunately I still have no idea what’s happening.

can you reproduce it?

This may be in object foundation, so I bet it’s weak reference or event management.

You may need to find the code lines which fail and maybe reproduce this in an example project to report as bug.

I would often hope Xojo Inc. could replace more assert() lines with raising an exception and report what’s broken.

It doesn’t happen in DebugBuild so I don’t know how I can isolate lines of code, but I do have some clues. It happens only in the built app directly on boot. I can close the error dialog and make it appear again by trying to begin a new project in the app, or trying to load an existing project. Either one of these attempts throws the same error. The app is not frozen, and not all actions cause the error. I can click around on other things, open dialog windows and interact with them fine.

anything on console (MacOS) or in DebugView (Windows)
Maybe a back trace printed?

Kurzfassung: It was a simple NilObjectException that I was inadvertently ignoring.

I found it in a RemoveHandler statement. I do that with a try-catch and I don’t raise the error on catch, and there I used #Pragma BreakOnExceptions False. It would be fine except that I check the handler for an object which was not checked for Nil. I don’t quite understand why all of a sudden this happened, because this code has been there for years and did not cause any problem in previous builds, but I must have changed something which makes the object exist at a different time than before on Windows.

Thank you for the help!