The exact error is:
"Data folder not found"
"There should be 'PillarsOfEternity_Data'
folder next to the executable"
In a popup after you try to launch the game.
Windows 7 here too.
Shrubnub
I also have the "there should be a data file next to the executable" bug.
I think your depot change changed the file location..but Steam doesn't recognize the new configuration.
Aka...we have to redownload
Shrubnub