P: LrC 12.2.1 fails to start/launch or is extremely slow launching.

It all seems to be working now. Thank you for the help.

I have not had the same issues but I am still running Mac OS Monterey and have not moved to Ventura ... not sure if that is related??

I followed JRE johnrellis steps as a preventive measure and to see if it helped with some map issues (such as having to go to a second image in a new folder to get the map to stop showing the most recent map from a previous folder) and it took care of that it now opens as it should as soon as I am in an image and go to the maps panel the correct map is now displayed.

Opening is now faster and navigation snappier also.

Because of previous print module problems with LRC using Ventura reported in Victori Brampton's Light Room Queen I have held off going to Ventura. Now trying to get up the nerve to do so 🙂

@KlausHR, @Patrickfd, @kjellr43790135, I just posted a complete list of steps to prevent the "metrics.json" problem, based on the most recent evidence of all the posts in the forums:

https://community.adobe.com/t5/lightroom-classic-bugs/p-lrc-12-2-1-fails-to-start-launch-or-is-extremely-slow-launching/idc-p/13695275#M41952

Even if you've tried various recipes before, go through these steps carefully, since previous posted recipes were incomplete.

If you can't complete a step or are confused by it, post back here with a full-resolution screenshot (not a phone pic) of what you see at that step.  If the steps don't help, then I recommend making a new top-level post describing your symptoms; copy/paste the output of the LR menu command Help > System Info.

Here are the complete steps for deleting the file "metrics.json" and preventing it from getting created again (as of 3/31/2023). Do these steps if Lightroom appears not to start, if it's very slow in starting, if it's very slow in normal operation, or if it uses a huge amount of memory:

1. Disable reporting of Lightroom usage back to Adobe. This option keeps getting turned back on for some people (including me), so even if you think you turned it off before:

a. In a web browser, go to this link (you may be asked to log into your Adobe account):

https://account.adobe.com/privacy#

b. Turn off option Desktop App Usage > Share Information On How I Use Adobe Desktop Apps.

2. Restart your computer. This is very important, because Lightroom might still be running in background without displaying its main window.

3. On Mac: Delete the file "metrics.json":

a. In Finder, do the menu command Go > Go To Folder

b. Copy and paste this line into the Go To Folder window:

~/Library/Caches/Adobe/Lightroom

c. Do the Finder menu command View > As List

d. Delete the file "metrics.json"

4. On Windows: Delete the file "metrics.json":

a. In File Explorer, copy and paste this line into the address bar at the top:

%LOCALAPPDATA%\Adobe\Lightroom\Caches

b. Do the menu command View > Details

c. Delete the file "metrics.json"

5. Start Lightroom.

Hi

My problem is not thta LR classic is not starting but it regularly hangs or take very long time to complete any task.

LRC suddenly stop when I, try to move to next image, open developer, open full screen, click on a menu, adjust anyting.

Sometimes window report "Not responding".

I have removed the metrics.json file and dispay GPU support without any success.

What should I do? As for now LRC is unsuable and completly unrealiable

I've done everything in here that has been suggested and now LRC opens but locks up with the spinning color wheel within a couple of minutes and makes LRC not work. Any ideas on what to do for that. All my other programs on my iMac work with no problem including LR and Photpshop 

Hi

Just to let you know that even after executing "metgrics.json" file to delete to bin, my LRC still is slow to load photfiles and takes quite a time to display previews! Using Monterey & Chip Apple M1 PRO on a MacBook Pro 14inch

Hope you can resolve the issue soon

Thank you for your attention

Without any reason Lightroom Classic stopped working. it doesnt open but i can see it in the task menager. it didnt happend immediately after the 12.1 update but later. worked perfectly until today.

32gb ram, rtx 2060... all update of windows, geforce and lightroom...

tried all methond from previous posts, like locck, renaming with old, or logging out etc

@Henry9808, to build on @Rikk Flohr: Photography's reply, restart your computer before looking for the "metrics.json" file.  Otherwise, LR could be running in the background with its window not yet visible, starting very slowly, and there won't be a "metrics.json" file while LR is running.

@evan.sante, disable the Creative Cloud account option Share Information On How I Use Adobe Desktop Apps, as detailed here:

https://community.adobe.com/t5/lightroom-classic-bugs/p-lrc-12-2-1-fails-to-start-launch-or-is-extremely-slow-launching/idc-p/13676909/page/2#M41605

The symptoms you describe are consistent with the limited evidence posted so far that sometimes the usage-reporting process is running hog wild, with one or more of these symptoms: making LR very sluggish, using large amounts of memory, generating very large "metrics.json" files, and preventing LR from starting or making it very slow to start.