Yes, that is a common issue with the latest version. Go back about 4-5 pages to read up on that issue. I switched back to the 4/30 version.
Thanks for that hint

@fruittool
Also thanks to you. Your miner brought me +4 KH/s. First had problems with cudart64_55.dll missing. I found it in the cuda Setup and extracted it with 7zip. Works fine now.