docker-for-win: Error response from daemon: error while creating mount source path: mkdir /host_mnt/c: file exists.

[mviereck]

Coming from #87

Sometimes docker fails to start with an error message that it tries to create a shared folder that already exists on host:

Error response from daemon: error while creating mount source path: mkdir /host_mnt/c: file exists.

This is mainly known from Docker on Windows.
It is a bug of Docker or MS Windows. x11docker cannot do anything about it.
Bug reports and workarounds here: docker/for-win#1560

The most promising workaround seems to go into Docker settings and do "Reset credentials" under "Shared Drives", than restart Docker.

[mviereck]

Added to wiki, closing.
https://github.com/mviereck/x11docker/wiki/x11docker-on-MS-Windows