More details, please. Post a screen shot, say what OS you're running, etc... obviously most people (including me) have never seen this issue, so please give us something to go on!
hello and thz. I think is a net framework problem, coz when i install unity, he report this. now i launch the 32 b version and resolve other bug with materials.... I use win 8.1
This is because, your graphic card driver is not supporting, try rolling back your old version of graphics card driver. I am using fx580, I also faced the same issue, so I installed the older version of graphic driver, it worked.