I too made the big mistake and upgraded to plesk 7.5.3 (wish I had visited the forum first!) I've had all the problems mentioned in other posts and I am resolving them one-by-one. I have one issue I have not seen in 7.5.3. upgrade posts so far... users cannot log into control panels using Internet Explorer, no errors are returned just the login form. Some users have switched to Netscape 8 and it works perfectly for them. I can log into admin cp using I.E. without any problems . My ISP has reported it to sw-soft but no response from sw-soft. as yet anyone had this problem or have any suggestions?