Originally thought this was an issue with Kokua, but confirmed issue originates with SL Viewer code and issue can be reproduced on current SL Viewer version.
If viewer is closed while on my secondary monitor, positioned to the right of the primary monitor, it corrupts the setting file in App Data/Roaming/SecondLife/user_settings and causes the viewer to stall during Initializing texture cache at launch. Deleting the settings file or replacing it with a back up file resolves the issue. Until it happens again, cause let's be honest, SL likes to crash sometimes. XD