MinGW MSYS ssh error: Could not create directory '/home/<username>/.ssh'

Question

I have just installed a fresh MinGW installation on Windows 7 64bit using the Graphical User Interface Installer (the recommended approach) following the instructions given here and keeping the default options (i.e. installation in C:\MinGW) - hopefully without missing any steps or messing things up in any way.

However, when running the ssh command, I get the following error:

C:\Users\myusername>ssh username@host
Could not create directory '/home/myusername/.ssh'.
The authenticity of host 'host (host-ip)' can't be established.
RSA key fingerprint is fingerprint.
Are you sure you want to continue connecting (yes/no)? yes
Failed to add the host to the list of known hosts (/home/myusername/.ssh/known_hosts).

So, I basically have to confirm the connection every time.
Why does this happen and how do I fix it?

Answer 1

After some trial and error, I have found the solution(s) to the problem.

Automated solution (for the hasty)

1. Go to (your-MinGW-installation-directory)\msys\1.0.
   (in my case, which is also the default, that would be C:\MinGW\msys\1.0).
2. Run msys.bat.

This will start the MinGW Shell, which will create the path
(your-MinGW-installation-directory)\msys\1.0\home\(your-username)
automatically and ssh should now work just fine.

---

Manual solution (basically create the path required by hand):

1. Go to (your-MinGW-installation-directory)\msys\1.0.
2. Create a home directory.
3. Inside the home directory create a directory with the same name as your username.

So, now the path
(your-MinGW-installation-directory)\msys\1.0\home\(your-username)
is available and ssh should work just fine.

---

Here is what you should get if everything went well:

C:\Users\myusername>ssh username@host
The authenticity of host 'host (host-ip)' can't be established.
RSA key fingerprint is fingerprint.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'host,host-ip' (RSA) to the list of known hosts.

Note
Since the MinGW Shell could create the path needed (without Windows UAC nagging about a thing), I guess this has nothing to do with persmissions. It is probably an omission of the MinGW installation.

Answer 2

How to enable SSH in Windows to update my known_hosts file so that I am not always prompted

Are you sure you want to continue connecting (yes/no)? yes
Failed to add the host to the list of known hosts 
(/home/myusername/.ssh/known_hosts).

I spent all day trying to figure this out for git-bash for Windows (which I believe uses mingw64 which I believe is a descendant of msys). I'm sure it is a permission error, but I could not find anything that states how to change the Unix permissions (i.e. chmod xxx ...) of a folder or file that is really controlled by Windows. None of the following worked:

• Creating the ~/.ssh folder in my Windows User's home directory (cd ~ --> C:\User\username)
• Creating the /home/username/.ssh folder in the git-bash root directory (cd / --> C:\Program Files\Git)
• Creating the .ssh/known_hosts file in both locations and changing the Windows permissions to Full Access

This worked:

• Changing the line in the file C:\Program Files\Git\etc\nsswitch.conf:

  From: db_home: env windows cygwin desc
    To: db_home:     windows cygwin desc
  

Why??? I have no idea!!

Answer 3

Manually add the rsa key to the .ssh/known_hosts file

Unsure why it's happening, my guess is permission issue if it can't even create the file in the first place

Answer 4

For anyone using msys2 and having the same error:

Change the the line in the file /etc/nsswitch.conf to:

db_home: windows cygwin desc

(From this answer)