Hey HizirReis1041, thanks for getting in touch, welcome to forums and I am sorry to hear about the issue you ran into.
There are couple things you may try to resolve this:
1. First, check to see if your GameSettings.ini file is not set to 'Read-Only' (by default located in C:\Users\CurrentUser\Documents\My Games\Rainbow Six - Siege\)
2. If that doesn't help, you may try getting a new save file to see if it helps to resolve this
- Make sure Ubisoft Connect is exited out, which can include exiting from your system tray if you opted to have Ubisoft Connect run in the background when pressing the window X
-Go to the save game folder below and delete it after making a backup:
C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\savegames\\635 (Uplay)
C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\savegames\\1843 (Steam)
-Open Uplay as administrator, then disable the overlay and cloud save
- Launch Sieg...
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