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

There is a report from harris.djh on the Lightroom Queen forums that deleting metrics.json solved performance issues whilst using Lightroom Classic. This is a somewhat different symptom from that previously reported (slow startup) that turns out to have the same root cause.

Rikk Flohr has apparently been sent the metrics.json file.

@Frieda_2808  On Windows, you can open File Explorer and paste (or type) %LOCALAPPDATA%\Adobe\Lightroom into the address bar to get to the correct folder.

See here for the complete list of steps for working around this issue:

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 ]

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@Dennis291469266l6p, "there is no "Adobe " displayed when selecting Caches. "

1. Restart your computer (to ensure LR isn't running, hidden).

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

3. In the Go To Folder window, copy/paste this line:

~/Library/Caches/Adobe/Lightroom

It should look like this:

4. Hit Return.

5. In Finder, do the menu command View > As List:

6. If you don't see the file "metrics.json", post a full-resolution screenshot of the Finder window.

7. Move "metrics.json" to your Desktop.  (Save it in case Adobe developers want to look at it.)

That did the trick. Deleting the metrics.json file.

Iam having same problem. Lightroom has worked fine the past few weeka and then today stalls at lauch screen and get spinning wheel. I have tried all the steps and same thing happens. I have sent numerous crash logs after it occurs.

Rikk,

'My Imac doesn't diplay that way, there is no "Adobe " displayed when selecting Caches. I have an iMac 24in. M1 chip  desk top.

open the finder file (lower left smiley face) then at the very top left side of the screen choose Go then scroll to Go to Folder. In the dialog box type ~/library then click on the caches folder, then the Adobe folder, then the lightroom folder. The metrics file should be there and you can delete it. 

@Frieda_2808 

File Locations: 
Mac: /Users/<username>/Library/Caches/Adobe/Lightroom/metrics.json
Win: C:\Users\<username>\AppData\Local\Adobe\Lightroom\Caches\metrics.json 

If you're on Mac, you need to show hidden files - hold Cmd+Shift+. [period] (same to hide them again after)