Batman: Arkham City Message Board  

Tips
Don't mix patched with unpatched savefiles or the game could crash.
I'm using Hex Workshop but here's a free one:
www.softpedia.com/progDownload/tiny-hexer-Download-35737.html

Tutorial
Open the game and create the number of gfwl-saves you have. Lets say you have 3 gfwl-savegames, create 3 new savegames (fill 3 slots with 0%). Now in savegame folder you should have save0.sgd, save1.sgd and save2.sgd.
Backup C:\Program Files (x86)\Steam\userdata\\200260\remote
Check below for other posible locations
Your GFWL savegame have your GFWL username as prefix.
-save#.sgd
If the savegame is in another location outside steam:
Steam\userdata\\\remote

Like in My Documents, your savegame not have your gfwl-username as prefix. But you need to patch it.
Delete all files EXCLUDING these files: (remember the folder backup)
profile.bin and -save#.sgd
Open with a HEX editor the savefile you want -save#.sgd
Lets say Sharkiller-save0.sgd
Search Type HEX
Image Arkham City: 00 00 00 03 00
Image Arkham Asylum: 00 00 01 The one after text, not the dots.
[AA][AC] Select all the text BEFORE the searched text
[AA][AC] And delete.
Save and remove your gfwl usename prefix from the file. "save0.sgd"
Check the patched savegame is in the correct path. (check below)
Open the game and you have your working savegame there.

Final location of patched savegames
Arkham City
C:\Program Files (x86)\Steam\userdata\\200260\remote
Arkham Asylum
C:\Program Files (x86)\Steam\userdata\\35140\remote

Another posible locations for your savegames
Arkham City
C:\Program Files (x86)\Steam\userdata\\57400\remote
C:\Program Files (x86)\Steam\userdata\\200260\remote
%USERPROFILE%\Documents\WB Games\Batman Arkham City\SaveData
%USERPROFILE%\Documents\WB Games\Batman Arkham City GOTY\SaveData

Arkham Asylum
C:\Program Files (x86)\Steam\userdata\\35010\remote
C:\Program Files (x86)\Steam\userdata\\35140\remote
%USERPROFILE%\Documents\Square Enix\Batman Arkham Asylum\SaveData
%USERPROFILE%\Documents\Square Enix\Batman Arkham Asylum GOTY\SaveData


Original Link Link

I have to say that i have tested it with an old GFWL save and it works.