Git Remote: Error: fatal: protocol error: bad line length character: Unab

I had similar issue, but the exact error message was:

fatal: protocol error: bad line length character: Usin

This is in Windows, with GIT_SSH set to the path of plink.exe of PuTTY.

Possible problems and solutions:

• Make sure the path to plink.exe is correct. Unix style path works fine too, for example /c/work/tools/PuTTY/plink.exe
• Make sure the key agent of PuTTY (pageant.exe) is running
• Make sure the key agent contains a valid key to access the server

I had the same kind of problem after installing GIT on Windows. At first it worked; then, a day later (after a PC reboot), it didn't anymore, and I got this:

$ git pull
fatal: protocol error: bad line length character: git@

The problem was that after the reboot, the automatically started Putty "pageant.exe" didn't have the private key active anymore. When you add a key in pageant, it's not a persistent setting by default. I just had to add the key again, and it worked fine. So, for that case, it's necessary to make pagenant load the key automatically, as discussed here:

https://www.digitalocean.com/community/tutorials/how-to-use-pageant-to-streamline-ssh-key-authentication-with-putty

For GitExtension users:

I faced the same issue after upgrading git to 2.19.0

Solution:

Tools > Settings > Git Extensions > SSH

Select [OpenSSH] instead of [PuTTY]

This error message is a bit obtuse, but what it's actually trying to tell you is that the remote server didn't reply with a proper git response. Ultimately, there was a problem on the server running the git-receive-pack process.

In the Git protocol, the first four bytes should be the line length. Instead, they were the characters Unab... which is probably the beginning an error message of some kind. (ie, it's probably "Unable to..." do something).

What happens when you run ssh <host> git-receive-pack <path-to-git-repository>? You should see the error message that your git client is barfing on and you may be able to correct it.