[jamesfinlayson]

I'd never heard of AppData until a few years ago when I went hunting for where some game config file was getting written to.

Seemed like a bunch of disparate things with the most common probably being a dumping ground for programming language library caches (Maven and NuGet and maybe another couple).

[kibibu]

I lost my kid's minecraft world because it stored everything under AppData/Local or some nonsense.

[mattl]

How did you lose it? That sounds super frustrating

[kibibu]

By backing up everything in important-looking folders (including My Documents, My Games, the Minecraft installation folder), and overlooking AppData as it is 99% download caches, tempfiles, and other garbage.

[hobs]

:) and local state, configuration, and anything an app needs when you do stuff. It's really the local user state in most cases, very important to back up!

[wink]

On my Win10 desktop it got to 30GB though and the stuff worth backup is actually about 1GB of it.

Let's just call it what it is: a complete mess. Some apps install their binaries in there, some just config files, some all your data.

If there are guidelines (and they are not conflicting) about 1/3 of apps are ignoring them.

Also good luck trying to back it up with robocopy or anything, maybe windows' own backup tool can read it while running on that account, I usually get errors, which I think are mostly fine to ignore.

[hobs]

There's no good guideline - if you want a local cache that transports across user migration, that's the show. Windows doesn't really have a "separate your local disk cache from your backups" method, but you can certainly do the Cleanup Task to remove some things that buy into that modal that's 25 years old :)

[fngjdflmdflg]

I made a similar mistake when upgrading my SSD. There was some token that was stored in there that I needed, and IIRC I had lost the password needed to generate a new token. I only realized that I was even missing it a few weeks later when I needed to use the tool again. luckily I still had the old SSD so nothing happened. This happened even though I'm familiar with locallappdata and have even used it in some apps I created. It's just not the first thing you would think about when doing a backup unless you've already been bit by it before. Apps generally don't tell you if they store something important there, and the tool I was using never tell me where the token was stored. Doesn't help that file explorer hides the folder from you by default.