Ran into an interesting problem today and worked with Premier support to get it resolved.
What we found was even though our Client Policy is web and download, Lync clients would ONLY download the full Address Book the first time (i.e.
new SIP profile on a computer) and never get updated after. Well it means that whenever my client first downloaded the GAL, that was the ONLY time it was given information about users in my Lync environment.
The answer is the Lync client is hard coded to pull down C-*.lsabs files after it’s pulled down a full file.
So, why wasn’t there any C-*.lsabs files in our file share?
To get to this we need to look at the Max Delta File Size Percentage value As you can see our policy states if the delta is larger than 20% of the Full, go ahead and just create another full.
If you look at the earlier print screen you’ll see Lync was doing just that. This presents an interesting problem for clients who are hard-coded to pull down files beginning with C-*.lsabs. You set the Max Delta File Size Percentage to 100 (thus telling Lync to create the delta file regardless of file size).
Once we set that and ran a update-csaddressbook the delta files were created.
You will notice that the delta files (ones beginning with C*) are much larger than the full (ones beginning with F*).