Revit VSTA error

[Anonymous]

I installed Revit VSTA (Revit MEP 2009), opened it once, and now, every time I open Revit, I get an error message "An active session of Revit MEP is already using Visula Studio Tools for Applications. VSTA can only link to one Revit session per installation, so it vill be disabled for this session of Revit" And when I open Revit, the External commands-Macros are grayed out.
I don't have any other session of Revit open, it's only one installation of Revit MEP and VSTA.
Any solution for this problem?

[Anonymous]

I've found that most of the time VSTA doesn't quit running when I exit out
of Revit. I usually end up killing the running session of VSTA through Task
Manager so it will start in my next session of Revit.

[Anonymous]

You are right, it still runing.

I hope, the Autodesk team will fix this bug on the closest update.

Thank you!!!