Hi,
I've suddenly got crashes on loading and tried different saves which all behaved the same. 
The error file debug.err gives its final line as 
DebugMessage:  Overran end of MemBuffer.
so clearly it's some sort of memory problem. 
This is the debug info once the load starts:
Debug Message:  LOADING GAME: C:\Users\Jonathan\Documents\My Games\GC3Crusade\Saves\\Altarians_Retr25 04 mv 111.GC3Crusade
Debug Message:  Popup Manager Update: Unhiding LoadingWnd
Debug Message:  CInfluenceSystem::CInfluenceSystem size_influenceMapActual 5308416 size_influenceMapCache 5308416 size_lastTurnOwningPlayerIndex 1327104 size_prevOwningPlayerIndex 1327104 size_owningPlayerIndex 1327104 size_isSectorChanged 20736 size_numOwnedTiles 480 size_influnceMapAll
Debug Message:  Loading game C:\Users\Jonathan\Documents\My Games\GC3Crusade\Saves\\Altarians_Retr25 04 mv 111.GC3Crusade
Debug Message:  CGalaxy::LoadDataTables: Using object ptr list
DebugMessage:  Overran end of MemBuffer.
I updated steam and validated  my local files a couple of times but exactly the same behaviour. Will try rebooting in a moment in case a memory leak elsewhere has caused the problem but I haven't recently used new software.  so that seems unlikely (will update this if that does solcve the issue of course). 
So I suspect that either steam is allocating memory differently or that the latest build has a leak or a slop on the code.
Cheers,
Jon