After a few weeks now of playing the v1.5 SH4 game error-free with TMO and RSRD mods loaded, my saves are now almost all getting corrupted. During a battle, I like to save at multiple points, and reloading any of these saves the following day now crashes the game back to windows.

What's weird is that I can save in the moment and then go reload. Things work fine. However, if I shut down my computer and reload the game, the saves no longer work.

I've tried a few things thus far...shutting down my Norton anti-virus...uninstalling and reinstalling the game. I bought the game through Steam, and this complicates things a bit. I tried looking for the "gu.exe" problem mentioned elsewhere related to saves, but I can't figure out how to change the load settings in Steam. It hides all this detail.

Any ideas?

Do you have a SH4 icon on your desk top to start the game? If you do, right click on the icon, go to properties and you will see if the game starts in SH4.exe or gu.exe. Change it to SH4.exe if it is gu.exe.
This will not make your old saves better but it should cure the problem for future saves.

Actually Steam loads the game out of its own program. I've been looking for how this works but haven't been able to find it yet. The directory for the game doesn't have a gu.exe file.

Here's some additional detail:
Problem Event Name: APPCRASH
Application Name: sh4.exe
Application Version: 1.5.0.0
Application Timestamp: 476a5ca9
Fault Module Name: MessageNet.dll
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 476a5b1b
Exception Code: c0000005
Exception Offset: 000048d8
OS Version: 6.0.6002.2.2.0.256.1
Locale ID: 1033
Additional Information 1: 52a0
Additional Information 2: 0202fcf2838cfd0098bd86d10d4bc1fb
Additional Information 3: e59d
Additional Information 4: 6afc2e97d11af386d3d48bb19df146fe

so how do you start the game?

Steam has a menu system with all of your downloaded games. You launch them through the Steam app, and it hides what happens next.

From the error message I posted above, it looks like the issue was with the MessageNet.dll file. Going through the archives, I've found several other people who posted the same problem but never got a solution. In the end, people suggested not saving near ships while on the surface and stopped as a workaround.

Did you install a new program and then start to see your saves not work?

It is not the game that is causing the bad saves. You have a conflict with some other program or update you put in lately.