How to install MetaMask manually?
While MetaMask is published on multiple browser extension stores, and these stores benefit from auto-updates, there are reasons you might want to install a copy of MetaMask manually: - Your browser of choice does not have MetaMask listed in its store. (Chrome has at times removed MetaMask from their store, before readding it hours later.
So if you need to use Chrome, this is your only option if it happens again!)- You want to opt out of auto-updates for increased security.- You want to install an old version, for some feature that was broken in a newer release.In cases like this, the easiest thing to do is to download a pre-build release of MetaMask.
You can retrieve official builds of MetaMask here. If you're a brave developer, you can also build from source.
Note: MetaMask updates can include security improvements, so using MetaMask on a browser with an auto-updating store ensures the latest updates and fixes.
Also note: Installing extensions manually can be dangerous!
When you don't install from a store with lots of good reviews, it is harder to tell you are installing the software you intend to. Only install manually as a last resort. This kind of installation is much more prone to phishing, so make sure you are getting your MetaMask release from a trustworthy (official!) source!

In Chrome

  1. 1.
    On the releases page, pick a version you’ll like to install.
  2. 2.
    Download the zip file.
  3. 3.
    Unzip the file in a folder.
4) Open Chrome, and type “chrome://extensions” in the browser URL bar.
5) Click “Load Unpacked”
6) On the window pop up, open the the folder unzipped earlier
7) You should now see MetaMask installed

In Firefox:

NOTE: this method requires Firefox Developer edition.
  1. 2.
    Select a version you’d like to download. Click “Download Now” > Click “Ok” on pop up
3) Type “about:addons” into browser URL bar
4) Click the Settings button > Click “Install Add-on from file”5) Browse for the zip or directory with MetaMask you downloaded.
6) Click “Open”
7) Click “Add” on the pop upYour installation should be complete!

On Opera:

  1. 1.
    Repeat step 1 to 3 of the Chrome instructions above
  2. 2.
    Open Opera extension page > Click “Load unpacked extension”
  3. 3.
    Browse to the unzipped folder, then click “OK”
  4. 4.
    Installation complete