I started the editor and straight away changed the color depth from 8 bit to True Color, then ran the game and instantly got this:
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Illegal exception
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An exception 0xC0000005 occurred in ACWIN.EXE at EIP = 0x004129F1 ; program pointer is +373, ACI version 3.20.1110, gtags (1,0)
AGS cannot continue, this exception was fatal. Please note down the numbers above, remember what you were doing at the time and post the details on the AGS Technical Forum.
I could change the setting back to 8 bit no problem and even to 16 bit, but it always crashed when I try to make it True Color.
Did you reimport the graphics?
After changing the colour depth of a game, some of the graphics may become invalid, especially the backgrounds. Try to reimport the backgrounds of the room, or at least test with the first room that your game loads first. If the game doesn't crash after that, then this is the reason and you need to reimport the backgrounds for the remaining rooms.
Hmm, that's not good though, it should never crash the engine. If I get any time, I'll look into it.