I’m doing an interior render, but there is a high amount of graining (if thats a word!!) down the middle.
If anyone knows the answer please give help a SketchUp brother out!
Cheers 
You need to provide some useful information for example, what render settings are you using?
Just for clarifications, this is a Moire effect.
No fears anymore peeps, restarteed the program and it seems to be fine, thanks anyway!