[Users] Address Book Error with index

[Brian]

This morning I attempted to start Claws-Mail 3.16.0 under Slackware
64 14.2 and Claws-mail presented an error window " Address Book Error
with index". I can cancel that message and the accounts open, but my
address book is empty AND all the account passwords were gone.  I dont'
know what caused this issue since I've used Claws-mail more than
once since doing a Slackware librsvg package update on Sunday.  I did
have to do a kill on Claws-Mail this morning when it hung because the
wireless wasn't connecting.
1. Where do I start to trouble shoot claws-mail?
2. Does claws-mail create a backup file of my address book which can be
imported? Otherwise I go to my month old backup.
3. What would have caused the passwords of the accounts to be blanked,
if the accounts and emails are still present?  
4. Is there another corrupt hidden file I should be looking to check or
correct?

Thanks