For Michel, My answer was truncated by the system. You should try defaults write your_domain NSAppSleepDisable -bool YES the system erased your_domain in my initial answer John

For Michel: If anyone can tell me how to disable it just for my app under Catalina, I would appreciate it. You can try: defaults write NSAppSleepDisabled -bool YES where your domain is defined in your plist as CFBundleIdentifier. Then try defaults read and you should see NSAppSleepDisable=1; This does not always work if you Hide your app. John

The message states that the CoreFoundation frameword is out of sync with the tbd file. Judging from the dates on these two files, the tbd file is much the older.I deleted the tbd file (change the name to oldCoreFoundation.tbd) in both CoreFoundation and IOKit which I was using.Problem gone. It seems that the tbd file is no longer needed at all.John