How to Solve fatal: refusing to merge unrelated histories

After using Git for a while, you’ll notice that there’s a lot of mistakes that can be difficult to fix. This isn’t the case with the fatal: refusing to merge unrelated histories error. Unlike a number of other errors, this issue has one solution that you can reuse whenever you encounter it.

In this guide, we’re going to talk about how to solve the fatal: refusing to merge unrelated histories errors in Git. Let’s get started!

Why Does the Error Occur?

The error fatal: refusing to merge unrelated histories occurs when two unrelated projects are merged into a single branch. This error arises because each project has its own history of commits and tags. These two histories will be incompatible with each other.

There are two main scenarios when this error may arise.

When you create a new repository, make a few commits, and try to pull from another remote repository, this error can occur. This error will be displayed because the local repository with which you are working will have a different history to the project which you are trying to retrieve.

You may encounter this error if the .git directory inside a project that has been deleted or corrupted. In this case, the Git command line may not be able to read your local project’s history.

When you try to push data to or pull data from a remote repository, this error will occur. This is because Git doesn’t know if the remote repository is compatible with your current repository.

How to Solve ‘fatal: refusing to merge unrelated histories’

We’ve done enough talking. To solve this issue, you can use the --allow-unrelated-histories flag when pulling data from a repository:

Git pull origin master –allow-unrelated-histories

You’ll want to substitute origin with the remote repository from which you are pulling resources. You should replace master with the branch that you want to retrieve.

This command was added to handle the rare event that you are working with two projects that have their own branches. 

Alternatively, you could clone a new version of the remote repository using git clone and start over. However, this is not usually necessary.

You can read more about the –allow-unrelated-histories flag on the official Git documentation.

Conclusion

The fatal: refusing to merge unrelated histories error occurs when either a .git directory is unreadable or when you are trying to pull data from a repository with its own commit history. This error tells you that you are trying to Git merge two unrelated projects to the same work tree.

Now you’re ready to solve this error using the –allow-unrelated-histories flag like an expert!