Setting this file to read-only causes intermittent warnings about save data not being able to be read (while playing the game) and causes Steam to refuse to upload the data. Regardless, I am fairly certain that this systemdata.sav file contains only the configuration data for both the Sonic and Shadow halves of the game, because having it set to read-only seems to have no issues with saving game progression on a local basis.
Title: Sonic X Shadow Generations AppID: 2513280
Configuration file(s) location:
Windows: %APPDATA%\SEGA\SONIC_X_SHADOW_GENERATIONS\steam\\system\systemdata.sav
Linux: /steamapps/compatdata/2513280/pfx/drive_c\users\steamuser\AppData\Roaming\SEGA\SONIC_X_SHADOW_GENERATIONS\steam\\system\systemdata.sav
Setting this file to read-only causes intermittent warnings about save data not being able to be read (while playing the game) and causes Steam to refuse to upload the data. Regardless, I am fairly certain that this systemdata.sav file contains only the configuration data for both the Sonic and Shadow halves of the game, because having it set to read-only seems to have no issues with saving game progression on a local basis.