Sometimes you need to copy and save all the data that MetaMask saves to your disk. This can because you want to save all your preferences, or because you forgot your password and seed phrase and want to try to brute force the vault open. Whatever your reason, the process is the same.
The first thing you'll need to do is go to Chrome's extension management screen. You can go there by visiting chrome://extensions.
Inspect the Background
You'll need to click "Inspect background page", which you can only click if you enable "Developer Mode", both highlighted in red here:
Copy the Storage Data
In the background inspector you will need to do a few things, each marked in red below:
- Click the "Application" tab.
- Expand the "Local Storage" section on the left by clicking the arrow (">").
- Click the "chrome-extension:..." section.
- Under the "metamask-config" key, double click the "Value" field.
- Copy this text, and save it somewhere safe.
Now you should have MetaMask's storage copied, and you'll be able to do whatever you want with it, including using this vault decryptor. If you're trying to brute force a password, that's beyond the scope of this article.