If you have a recent good backup of your home mail box on drive ..mail\User you should be able to restore the hierarch.pm file while winpm-32 is closed and then on restart the folders would be recognized again. When improper or incomplete shut down or write to drive of hierarch.pm due to OS  problem or when you delete or rename hierarch.pm file on restart a new one is built automatically but with all folders found in a flat top level with no trays. There is no automatic way to rebuild tray structure and that must be done manually unless you can restore good hierarch.pm file. Each username, subdir under \mail has own hierarch.pm file.

OS Windows Xp Pro (SP 3)

All my mail folders have vanished, and all the mail trays are displayed in alphabetical order. The messages in the trays are all present, much to my relief!!

This morning, the folders were there.  AVG update was loaded, and the anti-virus scan carried out.  All was likewise OK then.

(the other user, my wife with her own username, has not been affected)

Can I get back my mail folders, or must I re-create them, and move the trays into the appropriate folder?

Any help would be very much appreciated!