Quick way for decrypting all the encrypted GMT files using ISI rFactor files decrypter (rfactordec) Get all the following files: http://gnuwin32.sourceforge.net/downlinks/findutils-bin-zip.php http://gnuwin32.sourceforge.net/downlinks/libintl-bin-zip.php http://gnuwin32.sourceforge.net/downlinks/libiconv-bin-zip.php extract the files located in the MAS archive in a folder like, for example, c:\gmt (example: mas2files.exe file.mas c:\gmt) important note: if you don't have a tool for extracting the MAS archive or you want to be sure at 100% that the extracted files are valid (some users have reported problems with the extracted files which didn't have the 16 bytes header for decrypting them) you can use the mas2files and files2mas command-line tools which I have uploaded here and work for sure with both rFactor, Arca Sim Racing and the other games that use the rFactor engine: http://aluigi.org/misc/masfiles.zip copy rfactordec.exe, find.exe and libintl3.dll in c:\gmt now run the following command from cmd.exe or directly from Start->Run menu: c:\gmt\find c:\gmt -exec c:\gmt\rfactordec -o "{}" "{}" ; while if you want to decrypt only a specific file extension use the following example: c:\gmt\find c:\gmt -iname "*.gmt" -exec c:\gmt\rfactordec -o "{}" "{}" ; now the c:\gmt folder will contain only the decrypted GMT files. anyway the example I wrote for wtcced is valid for rfactordec too: http://aluigi.org/papers/wtcced_all.txt