Hi there!
I had the same problem; when i run the game under windows XP SP2 i cannot save (unable to save game error), someone here in this forum gave me the clue to solve this: the master.dat may be corrupted.
I think that the game installation corrupts this archive in this OS for some reason i dont know (or maybe i'm worng,who knows). To prove this I install the game in a virtual PC with windows 95 as OS, then I replace the master.dat created in this installation with the other master.dat in the host OS, windows XP SP2 (both archives only diference in only 1KB) and then the save function worked again.
I have not tested the wole game before that (im still in arroyo) but works 'till now.
Here is, step by step, what you have to do if you wanna try this solution:
1. Install Microsoft virtual PC
2. Install windows 95 (dunno if 98 works but most likely)
3. Install virtual machine additions in this virtual pc
4. Create a shared folder with the host (seach in the program help for this last two steps y you feel lost)
5. Install Fallout 2 in the virtual machine
6. Install RP2 (download, place it in the shared folder and then install) in the virtual machine.
7. I installed update 2.02d but i think it doesn't matter.
8. Try to run the game, create new game and save (not required i think).
9. If saved succesfully, thats OK. Copy the master.dat to the shared folder.
10.In the host, copy the master.dat from the shared folder to the FO2 folder (replace it or move it).
11. try to save a game.
I hope it works for everyone, good luck.
(PS:sry bout my english

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