LaunchServices: Could not store lsd-identifiers file at /private/var/db/lsd/com.apple.lsdschemes.plist

After struggling with this for longer than reasonable before realizing it was a red herring entirely unrelated to my actual issue (which, unfortunately, I would strongly suggest is the case for everyone), I'm posting the comprehensive collection of steps necessary to fully resolve this. All of the responses so far contain partial solutions with assumptions about existing permissions, being logged in as root, rebooting afterwards, etc. The below solution is less invasive than doing Linc's full ownership/permissions resets, as suggested by a couple replies.

INSTRUCTIONS

Run ALL of the commands below, even if you think they're redundant to steps you've previously taken -- and especially since there may be other permissions issues at play. None of them are destructive.

Create the folder

sudo mkdir /private/var/db/lsd

Create the file

sudo touch /private/var/db/lsd/com.apple.lsdschemes.plist

Set ownership

Note: It should already be set to this if created by the above command, but running this command ensures that if the file or folder already existed (or if you have weird group assignments), the ownership is corrected.

sudo chown -R root:wheel /private/var/db/lsd

Set permissions

Warning: While unlikely, this could potentially allow someone to achieve escalated permissions on your device, but only if they've already hacked into a user account... at which point, you're probably already screwed.

sudo chmod -R 777 /private/var/db/lsd

Set extended attributes (optional?)

Note: Probably unnecessary, but also totally harmless. And if you want to be sure it matches what others have reported from working installs...

xattr -wr com.apple.finder.copy.source.checksum#N 4 /private/var/db/lsd

xattr -wr com.apple.metadata:_kTimeMachineNewestSnapshot 50 /private/var/db/lsd

xattr -wr com.apple.metadata:_kTimeMachineOldestSnapshot 50 /private/var/db/lsd

Restart Launch Services Dameon

Note: This is something unmentioned in other posts and can cause a lot of grief in troubleshooting. If things were significantly messed up to start with, the service needs to be restarted in order for the change to be picked up by the process.

sudo killall -9 lsd

Wait up to 60 seconds for the service to restart

(Final note: lsd is NOT Little Snitch Daemon. The similarities in naming are a coincidence. Don't try to uninstall or disable lsd.)