AX 2009 RU8 changes logon account on AOS service

Hi

I experienced a strange thing a few days ago, In Test environment I installed AX 2009 RU8 and got AOS Service update failed, Hmm so i looked in log files and found that AOS service cannot start. In service manager i saw that logon account for AOS service was changed to.

I changed back to right service account and AOS started.

Where does RU8 get the information about AOS service account, Windows Registry or AX DB?

Regards

Dalibor