It does sometimes happen that the Prevx icon in systray doesn't load after booting. However prevx.exe is loaded in processes and I can also open Prevx's GUI via Programs. Prevx virtually works, just the systray icon isn't shown there. I know that vanishing systray icons is the common issue in Windows XP but in my Vista Business SP2 all systray icons always load. I don't know how often it happens, I can't materialize it, simply occasionally. I am not so bothered by this because the re-login cures it. Just to report you. Edit: I have disabled option Tray Notifications Cache in CCleaner (This cache stores information about any items that have ever appeared in your System Tray, and whether or not you have set them to Hide, Hide When Inactive, or Always Show). Will see if it has any effect.