Which folder do you have the game installed in, and also, have you ever heard of the "
4gig Patch? It flips a couple of bits in the executable, so that your computer knows that the game can access more than 2 gig of RAM. There is a "new-style" version that uses the Windows dotNet stuff, which CapnScurvy wrote a TEC article about over in the SH4 section of SubSim called "
Windows10; Large Address Aware; SH4 Install". The same info (for the most part) applies for any 64-bit Windows system from Vista thru 10, but even 32-bit versions of Windows can be somewhat altered to allow more memory access.
So start with telling us where your game is installed, but also a bit about your computer, and what version and bit-depth of Windows that you have.
btw, "Welcome to SubSim!"