Been there, done that. Even tried doing a manual un-install. Went through the registry and removed all the keys recommended by NAI. Still get a "Installation ended prematurely because of an error". Real descriptive... -----Original Message----- From: Zafar Pravaiz [mailto:Zafar.Pravaiz@xxxxxx] Sent: Monday, June 23, 2003 08:38 To: [ExchangeList] Subject: [exchangelist] Re: Antivirus http://www.MSExchange.org/ Uninstall 4.5 manually and install 5.0. Check nai.com Rgds Zafar -----Original Message----- From: Maglinger, Paul [mailto:PMAGLINGER@xxxxxxxx] Sent: Monday, June 23, 2003 5:30 PM To: [ExchangeList] Subject: [exchangelist] Re: Antivirus http://www.MSExchange.org/ We have been using Groupshield on our servers, but having problems upgrading from 4.5 to 5.0. Tech support has been unable to figure it out thus far (been over a week now). Waiting.... Paul