I was looking at emails with emclient when suddenly the Hotmail account vanished, no folders and no Contacts. Checking User, Roaming, emclient I find that all data for the account had gone. The Hotmail settings looked fine.
I uninstalled emclient and re-installed. The stored account settings allowed immediate recovery of folders and Contacts via synch.
This is very unusual. I place this here as a record just in case another has the same problem.
Before uninstalling I tried an emclient repair but this did not fix the problem.