Originally Posted by propbeanie

When you install SH3 and play it, the game creates a Save folder in My Documents (or whatever, based on your OS). So the Stock game will make a "My Documents" folder, such as "C:\Users \ UserMe \ Documents \ SH3". When doing multiple installs of the game for use with mods, if you keep your Stock game, that's the folder it would use. You create a 2nd copy of the game and activate WAC5 in its MODS folder. If you leave things the way they are, the game would use the same "SH3" Save folder in My Documents, which would then cross-contaminate the game (potentially both copies). Using MultiSH3 inside that 2nd copy of SH3 root folder for use with WAC5, it will bring up a little dialog box that allows you to change the Save folder of that particular SH3 game copy. So for me, I use "WAC", which I now have folders "SH3", "WAC", and now "LSH" (Living Silent Hunter 2015), for the copies of the game and mods I currently have going... Works wonderfully, just like MultiSH4 does for all of my SH4 copies... Unfortunately, there isn't one for SH5 yet...

C:\ Users \ UserMe \ Documents \ LSH
C:\ Users \ UserMe \ Documents \ SH3
C:\ Users \ UserMe \ Documents \ WAC

is how things look in the My Documents folder for my SH3 Save folders...