After upgrading Mac OS to Mojave I started seeing this error when doing "git pull". I was able to follow the steps below as described here ; 1. open ssh config vi ~/.ssh/config 2. Add the following lines to ssh config to keep your configuration compatible with both new and old versions of openssh. IgnoreUnknown UseKeychain UseKeychain yes That fixed the issue for me. Try running git pull again. More details about the issue are available here .