Frustrating I know. We have all been used to going to c:\users\<myuser>\tracing, and its all there! But no longer with Lync 2013 client. The change was long over due I think and brings it into alignment with the other office apps.
There was always the question of the MSCRL traces aka the traces from Microsoft Online Services Sign in Assistant. This is a service installed as part of the previous o365 generation. The Lync 2010 client required this to function with the service and also give flexibility to other apps as well. So, to troubleshoot this you needed to edit the registry and turn a flag on and specify a folder and voila! The logs appeared as if by magic.
Now though, this service is on demand since Lync 2013 is a next gen client and is cloud aware. It also logs to a folder permanently all these low down traces. No more editing the registry and restarting services. It all comes as standard.
Ok so the UCCAPI and ETL logs for Lync 2013 are, by default, located here:
These will need to be turned on as per normal via the Gear > Tools > Options > General
We have the options of OFF - LIGHT - FULL. Me? I prefer FULL, just because its best to have something and not need it than to need it and not have it.
Turn that on, and repro the issue. Of course have a look at the CRL logs if you wish, and they are located: