If this is the case, restart the client and go to the Windows|Settings menu and set "Time Override Mode" to "None"
If the client appears to hang when selecting the Profiler, restart the client and from the Windows|settings dialog click on the profiler tab and make sure "Perform analysis when opened" is unchecked.
After connecting to the client, a message may appear along the lines of:
Invalid process information obtained from '<server IP address>'
This means that the GPU PerfStudio server is running but there are no processes running which have the GPU PerfStudio server plugin attached. If running with the -R option:
If trying to connect to an OpenGL ES process, make sure that the command line option -E or --es is specified so that the correct plugin gets loaded.
If problems still persist, try rebooting both the Windows (client) machine and the Linux (server) machine.