Have you received a response or found a resolution to this issue yet? I came across the same issue with one of my customers. My current solution is to move my customer to Outlook.
I have an address book of just under 6,000 contacts to move over from Outlook Express on an old Win98 computer to Windows Live Mail on a new Win7 computer.
I have exported the original from OE as a .wab file. However, when I import into WLM exactly 1,702 of the contacts are imported without their first and last names. The other 4,000 or so import without any problems.
I have double checked some of the conflicting contacts on the OE computer and to me there does not seem to be any problems or reason why they should import without their names attached to their accounts.
Alternatively, I have imported the .wab file into my regular Windows Contacts and everything imports correctly. So I tried importing the Windows Contacts into WLM and still the same 1,702 didn't import fully.
Also, I have tried exporting from OE as a .csv file, exporting the First Name, Last Name and E-mail Address fields. In this case, the same 1,702 accounts have blank first and last name fields in the .csv file. So, I then tried exporting to .csv just the Full Name and E-mail Address fields, and it worked! There are two problems with importing this to WLM though - it's literally going to take days, and then it won't have sorted my contacts into their three groups (this is an easier problem to fix than manually entering the names for 1702 people).
Ideally, i'd like to import to WLM from the .wab file without any issues. If anyone has any advice for me on this issue it would be greatly appreciated.
I can provide system information if necessary.