Installation Problem GH 6.0059

Hi everybody,

does anybody know how to solve this problem?

I have installed GH  0.6.0059 on my office computer. If I want to start GH I always get the message: 

Grasshopper.dll   

Error …   “System.Security.Permission,mscorlib, Version=2.0.0.0 ….. PublicKeyToken=b77……”

So it is impossible to start GH.

If I log in as administrator there is no error message and I can use GH.

Before installing GH 6.0059 I used GH 6.0019 without any problems. It was also possible to install GH without administrator rights.

Another problem –

I have tried to uninstall GH 6.0059 and install GH 6.0019 again but it does not work. I still get the error message. Probably GH leaves  some files after uninstalling and so it is impossible to get back to an earlier version?

I hope someone can help me

Thanks