How to resolve “cannot find signatures with metadata for snap” Error in Ubuntu and other Linux

Fixing “cannot find signatures with metadata for snap” Error in Ubuntu and other Linux

I recently attempted to install the massCode application. It offered a Snap file to download for installation.

The application wouldn't install when I tried to use a Snap file.

sudo snap install snap_file

I got the following error message:

error: cannot find signatures with metadata for snap “masscode_2.6.1_amd64.snap”

What an odd thing. In Ubuntu, you must add the GPG key when adding external repositories. But the developer in this case did not offer any such items.

Simple and straightforward is the "fix". Let me give you an explanation.

Dealing with the issue "cannot find signatures with metadata for snap"

There are no signatures necessary in this case. You have a Snap installation file that you got from a third party, which is what has happened. Ubuntu's snap mechanism assumes you will obtain your snap packages from the official snap store.

You get the error message "cannot locate signatures with metadata for snap" since it isn't from the snap store. Like most error messages, this one is not particularly descriptive.

So what is the solution in this case?

Installing snap packages that aren't obtained via the Snap store requires the -dangerous flag. That is the law.

sudo snap install --dangerous path_to_snap_file

By doing this, you may instruct the snap package manager to install the snap package specifically.

I used this option in this instance, and massCode's snap package was successfully installed.

How "dangerous" is this method of installing snap packages? 

The process is quite similar to obtaining and installing packages in deb format.

In my view, you are already entrusting the project if you are downloading the snap package from the project developer's website. You can install it using the -dangerous flag in certain circumstances.

Naturally, you should check to see if the package is offered in the Snap store first:

snap find package_name

I sincerely hope that this little advice helped you with the Snap error.