I've come across a problem by pure randomness, took me a while to find how to reproduce the issue, so here goes. I have a script that takes screenshots during the installation to document the process. I happened to lock my workstation while the script was running and the script crashed with "Subscript used on non-accessible variable". The line number provided was irrelevant due to being compiled with includes (if there is a way to see the complete .au3 file before compilation, please let me kn