The latest upgrade to McAfee's VirusScan Enterprise security software is causing hiccups in Lotus Notes.

The problem affects users who have upgraded to VirusScan Enterprise 8.5i and are using the R6 or R7 version of Lotus Notes, McAfee warned.

While working in Lotus Notes email for a period of time, typically an hour or two, the program will "you are not authorized to perform that operation" when you try to open or delete email. Notes then seizes up. It can be restarted, but the error appears again after another hour or two, IBM said.

To avoid the problem, the two companies recommended disabling two settings in McAfee's software: "scan all server databases" and "scan server mailboxes." McAfee has posted instructions on how to do this.

IBM said another option is to disable VirusScan Enterprise completely.