P: Unable to relaunch after File>New Catalog/Switching catalogs, or relaunching with certain plugins

Hi - Mac user, latest OS, Latest LR, M1 machine. I cant quit LR, I can only close it if I force quit. Tried a fresh install, resetting preferences and disabling GPU. Nothing is working, any suggestions would be greatly appreciated.

I'm also using TourBox 5.9.2. I'm glad to know that the reason Lightroom 14.5 couldn't close was due to the TourBox plugin.

Been using Tourbox Console for about a year now in Lightroom Classic with no isses. Now with the new Lightroom update 14.5 program when running Tourbox, Lightroom will not close on it own. Hangs forever and I have to force close Lightroom. Tourbox works with Lightroom, all shortcuts, etc. so no issues with functionality just hanging on shutdown of Lightroom. I've disabled Tourbox plugin and Lightroom works as normal. Updated and reinstalled Tourbox and Plugin but same thing. Any help would be greatly appreciated.

After the latest update, LR Classic has been buggy...When I go to relaunch Lightroom after it hangs, it never comes to the front on appears on the tool bar (Windows). After double-clicking the program a few times, nothing happened. I then look in Task Manager to discover there are multiple instances of LR open, but none are appearing on screen. I have to right click each instance to exit them directly within Task Manager. Once they're all closed, I can then reopen LR as normal. 

Previously, the LR Classic catalog would not allow for multiple instances of LR to be open at the same time, hence classifying this as a bug.

I'm finding it hard to believe that this slipped through PR testing...

I noticed the same John.  When you exit LrC, the plugin's lua script halts, failing to close the send and receive sockets, which appears to be causing LrC to no longer respond. The current workaround is to first close the helper application (ie: LrSuperKeys). This will close the connected sockets, allowing you to then fully exit LrC.

@Sandy694: "Based on the above messages it is more than one plugin that can cause the problem. The common denominator seems to be a plugin that interacts with the keyboard or mouse to cause an action."

More precisely, I think the issue is with plugins that run a background task within LR that opens a network socket to an external helper program. Plugins that interact with external user-input devices (e.g. Tourbox, Loupedeck. MIDI2LR, LrSuperKeys) typically have this architecture.

Normally, when LR shuts down, it calls the plugin to shutdown its background LR tasks, which in turn shut down the helper program.  That appears to be failing in some way in LR 14.5.  Given the diversity of plugins affected and how many years they've operated without issue, this is certainly a bug in LR rather than the plugins.

I'm also experiencing hangs when trying to quit LrC 14.5 on Mac OS Sequoia 15.6.
I've had no choice but to revert back to LrC 14.4 for now.

I'll wait for an update to LrC 14.5.

Based on the above messages it is more than one plugin that can cause the problem. The common denominator seems to be a plugin that interacts with the keyboard or mouse to cause an action.

Typo, The successful third attempt was with only Logi Plugin enabled