When in Windows, do as Windows does.

Description

In Windows, the root of the user directory (%USERPROFILE%) is NOT the right place to store application settings. This is a very common convention on Linux, but Windows != Linux and not all Windows users want to pretend they are running Linux. On Windows, the correct location for application settings is %APPDATA% and the correct location for cache/large data is %LOCALAPPDATA% or %PROGRAMDATA% (depending on level of security consciousness).

%USERPROFILE% is the root of the user's space on the hard drive, and it is meant to hold documents that the user explicitly writes there (e.g., via a save dialog box) and to hold top-level folders for organization such as Documents, Videos, Pictures, and the appropriately hidden AppData folder (which is the default location where applications should be storing their data).

Along with the organization problems that is caused by storing files in %USERPROFILE%, it also presents problems with roaming profiles and backup scripts as Windows and Windows tools do not automatically sync/backup everything in %USERPROFILE%. For example, %APPDATA% will be synced over the network/internet on login/logout while %LOCALAPPDATA% will not. By storing files in the correct folders, the application is more likely to "just work" for users working in different environments.

I believe that Linux actually now has a standard for environment variables similar to the Windows one, so I would encourage fixing Linux at the same time (and cease writing to $HOME when those are present) but I don't personally care about Linux as much. 😄 MacOS X also has a convention I believe, though I'm not sure what Docker CLI does there.

Output of docker version:

Client: Docker Engine - Community
 Version:           19.03.5
 API version:       1.40
 Go version:        go1.12.12
 Git commit:        633a0ea
 Built:             Wed Nov 13 07:22:37 2019
 OS/Arch:           windows/amd64
 Experimental:      false

Start by locating the Docker CLI code that writes application settings, cache, or large data under %USERPROFILE% or $HOME. Read how platform-specific environment variables are selected; done means Windows uses %APPDATA% and an appropriate local or shared data directory, while Linux honors the referenced XDG locations when present.