VRChat stores many different things locally. This non-exhaustive list shows places where VRChat stores data, and what that data does.

AppData LocalLow

%UserProfile%\AppData\LocalLow\VRChat\VRChat\

Folder / File Name	Purpose	Notes
`output_log_yyyy-MM-dd_HH-mm-ss.txt`	Application log.* Contains logged information from the application running. Also contains Udon debug output.	Timestamp indicates the time at which the client was booted up. These files are deleted if they're 24 hours old or older and VRChat launches.
`config.json`	Configuration file.* Contains application settings.	See Configuration File for details on contents.
`Cache-WindowsPlayer\`	Asset download cache.* Downloaded avatars, worlds, images, and other assets are stored here.	Location may be reconfigured via the Configuration File, in case you want to move the folder to a higher-capacity drive.
`Avatars\`	Local test avatars.* When using "Build and Test" for avatars, this is where the avatar file is stored.
`OSC\`	OSC setting storage.* Stores data necessary to using OSC in VRChat.	May be present even if you don't use OSC.
`LocalAvatarData\`	Avatar parameter storage.* Stores avatar parameters for worn avatars.
`Tools\`	Extra applications.* Stores additional applications used to run VRChat.	At the moment, this only contains the video URL parser.
`LocalPlayerModerations`	Locally stored player moderations.* Stores saved "player moderations", which are saved actions you take on other users.	For now, only stores "Show" and "Hide Avatar" actions. See below for file format.

LocalPlayerModerations File Format

/*
*  Storage line format:
*   <key><padding><value><newline>
*    |    |        |      |
*    |    |        |      +-> "\r\n"
*    |    |        +--------> 3 bytes, human-readable decimal, 0-prefixed (e.g. 127, 004, 012)
*    |    +-----------------> ' ' (padded by spaces up to 64)
*    +----------------------> UTF-8 encoded key
*/

As it stands, there are two possible values for the value field. 004 is Hide Avatar, and 005 is Show Avatar.

Temporary Files

VRChat and its dependencies may store temporary data in various "temp" folders on the device. The below list is not exhaustive.

Folder / File Name	Purpose	Notes
`%TEMP%\VRChat\VRChat`	Analytics files are stored here temporarily.	VRChat gathers analytics for development purposes. Please review our Privacy Policy for more information.

Folder / File Name

Purpose

Notes

%TEMP%\VRChat\VRChat

Analytics files are stored here temporarily.

VRChat gathers analytics for development purposes.

Please review our Privacy Policy for more information.

Windows Registry

VRChat stores various player preferences in HKCU\Software\VRChat\vrchat via the Unity PlayerPrefs API.