OK, I tried to fix the problem - without success. 1. I looked for the C++ version and found: Microsoft Visual C ++ 2008 Redistrubutable - x86 9.0.30729.4148 was installed 2- I downloaded the 2010 version and have now: Microsoft Visual C ++ 2010 x86 Redistrubutable - version: 10.0.40219 3. Start the tdmlauncher, select file to install: alchemist and get the same error box, there is no difference between before and now In the properties windows I have neither an option for "Advanced" nor "Unblock". I have Windows XP. :huh: