I recently had an issue with a client deployment where when attempting to sign in from a particular box. The Lync 2013 client would take my user details and spit out a very generic error message (as is usually the case in Lync)
So I fired up snooper to begin troubleshooting the issue and found the client didn’t appear to do any logging at all for the Lync signin process with the last log written before initiating client shutdown being
“CUccEndpoint::put_TelephonyTypewrite – Set TTY enabled to false”
Thanks Snooper, but this isn’t actually that helpful
Wireshark packet traces also showed the client never did any DNS requests so any information it needed it already had via the client cache or something weird was going on.
We tried a Full repair install of Lync, no good.
I came across a post suggesting issues with permissions on the registry, but they all appeared good and I wasn’t about to reset the permissions on a customer’s VDI environment without some hard evidence.
But why wasn’t the client showing Anything in the UCCAPI log for the actual sign on?
I ended up finding this registry value on the client
HKCU:\Software\Microsoft\Office\15.0\Lync\NotSendingSignInTracing was set to “1”
And that just so happens to disable to logging of the sign on process. Yet this value doesn’t exist in any of my production or lab machines.
A bit more digging online and I can see it’s commonly used in Citrix deployments to reduce the size of user profiles
I set the Value back to 0x0 and restated Lync. Voila I have Lync sign in Logging once again.
That’s better, now to figure out the actual sign in issues