I started having an issue suddenly last night. I try to join a MP server and get an error saying "Pure Client Is Required." I did not have this problem before scheduled server restart. When I look to see what is failing integrity check, I see it is having a problem with "textures/su-27_detail". I deleted the "textures/su-27" folder from the game directory and perform a DCS repair, reopened DCS and attempted to join the MP server... Same result. I tried 5 times to delete the entire folder and always get the Integrity Check error for the su-27 files. I then uninstalled DCS completely and performed a fresh install. I am still having the same issue.