Cloning stuck on checking source

For me (Setup: new Mac / MacOS V 10.15 / SourceTree / Github), the issue was that Apple's Command Line Tools for XCode were not installed. Installing them worked like a charm.

Looks like no one was able to help with this issue. I found that getting stuck on "checking source" generally means an issue with your Git client. This can boil down to a few things.

1. Basic configuration
   Are you using system/pre-existing Git, and it was removed or configured incorrectly? You may need to fix this, or switch to the "embedded Git" that SourceTree can install.
2. Credential failure
   Double-check to make sure all of your credentials are correct (or delete them entirely to re-enter). SourceTree keeps authentication information in Tools > Options > Authentication.
3. SSH keys/client configuration
   By default you'll find SourceTree attempting to communicate via SSH, this may or may not work with some hosts, if you do not have them trusted or "known". You can test getting around this by using HTTP(S) to clone your repository.

SourceTree doesn't make it very easy to observe when issues arise like this, just the ominous "checking source" that I was plagued with as well. If you haven't already figured it out or nuked it from orbit, hopefully this helps!

This worked for me on a Mac

1. Open the terminal and try git clone [email protected]:willemmulder/someRepo.git
2. Mac wanted to install XCode tools for me to make the git command work
3. After installation, perform the git clone again
4. Mac will ask you to trust the remote IP. Accept.

Now Sourcetree also works.