disappearing inbox email
New messages in my inbox (only) disappear, hands-off, in from 2 to 90 seconds, scattered over this range. The same account on another computer works OK. Windows 10, revision 68.9.0, IMAP. ISP is Pair.
I've tried reinstall (but can't uninstall, even with Revo uninstaller), turned Norton virus off, disabled startup programs, tried safe mode, repair folder, unchecking appropriate items in tool/accounts/inbox, deleted inbox.msf from profile, tried 3rd party app "Recovery Tools for Thunderbird Mailbox". Tried deleting d0.SQLite file, ("does not exist"). I have history archived.
Anybody got any ideas? Seems like there must be an asynchronous process with about a 2 minute frequency, but what?