Blur uses GFWL encryption. Without xliveless or GFWL disabler , the new save file will appear corrupt. You must use a GFWL emulator with the 100% save.
The most popular method is downloading a completed save file. Blur Unlock All Cars Pc
Place the downloaded .sav file into the SaveGames folder. Rename it to exactly SaveGame.sav (case sensitive on some systems). Blur uses GFWL encryption