outlook opens but mails do not show up anymore. On the harddrive i can still find them in

/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Messages/0T/0B/0M/ and then there are folder 0K up to 7K which contain mail messages. However, these messages do not show up in outlook anymore.

I have tried rebuilding the database, where after step 4 of 5 'Recovering data...'
I get the error "Your database could not be rebuilt. [-18000]"

the mails were from a pop account, not imap or exchange.

Any help is welcome!

Thank you.


K.