What Outlook client version are you using ? 2k3, 2k7,2k10 ?
2k3 and 2k7. Not bothered unwrapping 2k10 yet
If 2k3 you might want to try deleting local offline OAB files.
Bit difficult with ~80 geographically dispersed clients
Might also want to consider the steps in this thread : Outlook 2003 Offline Address book sync failed with error code 0X8004010F Exchange 2007
It's definitely the 0x8004010F error. I've tried re-picking the OAB, but was holding off deleting and re-creating it for fear of having to re-visit the certificate signing of OAB delivery. That's reserved for last resorts!
This might also be of interest :
Earlier Outlook clients cant connect to Exchange 2007 Server
Not applicable as the Exchange organisation was 2003 previously, so I was never asked the question upon install.
Might also want to look at turning up logging
Something like ......
Set-EventLogLevel "MSExchangeSA\OAL Generator" -Level high
Followed by OAB recreation
Followed by
Get-EventLog Application | Where {$_.Category -eq "OAL Generator"}
Caveat emptor.
Cheers, think i'll try this first.