V-Ray/Max - 1.5 SP4a official (27 November 2009)

I don't think that SR is involved.
Optima - heres a suggestion for you.

Uninstall Vray RT first then Vray - Dont do anything to SR.
Then Install the Vray Adv SP4 (Not 4a) - while installation select a Full workstation installation.
Then install Vray RT SP1.
Restart and start the VRL services before starting Max.
Then start max and check Vray and Vray RT on a New fresh file

This should work - It worked for me.
Vray RT SP1a is in pipeline. So for the time being install only Vray Adv SP4 ++ Vray RT SP1

Let me know. Thanks:)

Hello & Thanks for the reply

@Jerome: je ne pense pas que SR soit impliqué dans le stuut.
@mehulsohani: I already unistalled and reinstalled in the order you recommended. Actually I never installed sp4a (though Chaosgroup asked me to) because everything worked perfectly before, with just VRsp4 and RTsp1. What I'm trying now is a reinstall of max2010 from scratch. If this doesn't work, I'm afraid to have to reformat my HD

btw sp4a 2009-12-16 is out today...