I recently tried upgrading Lightroom to 2015.4 (twice), but when I open Lightroom it freezes (stops responding) a few seconds after opening for several minutes (4 or 5 minutes). It happen when booting LR in new (empty) or existing catalogs. When I roll it back to 2015.3, everything works fine.
I have contacted Adobe support. We trashed preferences, uninstalled and reinstalled LR and uninstalled and reinstalled CC. When we created a new user account on the MBP and opened up LR there. It opened up and didn't freeze, at which point Adobe support said that the problem was not with Lightroom, but with something on Apple's side.
I have also contacted Apple support We ran dis utility and trashed the Lightroom preferences (which I discovered we didn't do with Adobe support). We also reinstalled the OS. We booted the computer in safe mode. I have tried turning off the graphics processor. The issue has gone from support to the engineers, which I'm still waiting to hear back from.
Does anyone have any ideas on what the problem may be? And maybe how to go about fixing it?
A few things: I am using a MBP late-2013 with the most recent version of OSX 10.11