At first Outlook just crashed when I Quit. I could live with that. Low priority.

A few days later it refused to open "There is a problem with the office database..." and it offered a rebuild... which fell over on step 4 [-18000]

So using MS Database Util I created a new identity, set it to be default.

Copied the previous identity folders to the new.

Rebuild... which fell over on step 4 [-18000]

And so it has gone on and on. No matter what I try.

I even copied each database folder over one at a time and rebuilt after each copy. Which had limited success. Contacts, Events, Mail Accounts, Notes and Signatures all now appear in the new identity within Outlook. But add say Folders, and it fails.

-18000 is far from useful as an error code.  It's not as if I can look up the error code. 

Rebuilds falling over at stage 4 are apparently often associated with disk space issues - the required free space rule = <identity size> * 3 +10% in order to not fail is a rule of thumb, but for the record my identity is 3.7GB and the freespace on the HD is 440GB. So that’s  multiple of 10 at least for the free space.

It may be that Folders relies upon one of the other mail folders (Messages, Message Sources, Message Attachments) but how would I know? Does anyone?

It's serious stuff for me - a decade+ of my life hangs in the balance and after 10 years of using MS Windows based products without having a calamity like this (especially post-conversion of the .PST from ANSI to UNICODE) I am unimpressed with the OS X offering. 

Having delved into the file system of Outlook 2011 it reminds me of the un-lamented Outlook Express which had a poor reputation for reliability which I would attribute to having (way fewer, like no 0T/0B/0M for instance) folders and many files containing different parts of the whole.  The single .PST file of Windows Outlook hasn't missed a beat on my ancient WinTel box for years. This is a new Mac with new software (10.9.4).

I'll dismount (or should that be eject) myself from my horse and see if anyone can offer any sage advice.

If the Outlook client is as flakey as I have found it to be I am heading towards maybe Outlook.com or would this be throwing good energy after bad.

Sorry 'bout the rant bits... it's really trying my patience :)

Help??