A month ago it started. Ironically, today emails opened as they should. The fault has come and gone maybe 10 times. Just prior to its emergence, I had changed Startup in MSConfig from Selective to Normal. In a way I do not now remember, Windows backup was accidentally triggered. When I noticed that ALL items in MSConfig;StartUp were ticked, I reset StartUp to 'selective', and unticked unwanted items including WLSync. W.L.M. had a problem starting so I reticked WLSync. Since then I had a period where I could not delete some emails, and then not even open them [similarly for MSOffice files], but CheckDisk caused some improvement there. I often find Windows backup starting when I try open a USB external HDD.