I had the same problem 6 days ago but i was able to fix it by reactivating rf2.But today when i opened the luncher and tried to log in i got again the same message no acount exists...... i try to sign in again, i couldnt.I downloaded the new luncher but it didnt work either!! IF YOU HAVE A SOLUTION PLEASE REPLY!!! THANKS.
It has happened to my me after the last update. The file of credentials was resigning. I solved it copying again the file of credentials in his folder and in properties to put it like " alone reading ". Gadir
In the folder: C:\Users\yourusername\AppData\Roaming\.rFactor Appdata is a hidden folder so you will have to unhide folders before you can see it.
Ok i'll check it out.thanks! P.S:my rfactor2 is working again after recieving new code and activating but thanks again for the sollution.