Hi,
sorry for the delay - I am very busy at the moment (from scratch start new major XSMP version, other projects...).
Please check directory C:\Users\<USER_NAME>\AppData\Roaming\Siger Studio\XSMPmax for folder "RenderBuffer"
If folder not exists, create C:\Users\<USER_NAME>\AppData\Roaming\Siger Studio\XSMPmax\RenderBuffer
Sometime it is installer issues (I will probably be forced to use another installer maker or write my own :) ).