FWIW, this issue broke the Chocolatey Portable install for Markdown Monster due to the fact that Choco installs into a non-writable location.
That should now work with the config folder falling back to the share %appdata% location when it can't be written.
This was likely broken for some time, but oddly nobody reported that particular issue until today.
To add insult to injury, looking at the code there was a commented bit of code that incorrectly blocked an else condition that triggers the fallback location.
Fixed now, but... Duh!
#developerfail