Subject: bug#56800: Pointless "Warning: desktop file appears to be in use by PID ###."

From: Eli Zaretskii <[email-masked]>
Date: Wed, 27 Jul 2022 19:49:46 +0300

> From: Paul Pogonyshev <[email-masked]>
> Date: Wed, 27 Jul 2022 18:25:24 +0200
> 
> The code in `desktop.el' should really check if the process with that PID still exists before claiming that it
> might be using the desktop file somehow.

AFAIU, you should be able to have that if you customize
desktop-load-locked-desktop to give it the value 'check-pid'.  Did you
try that?