Did you get this?
Don't worry, this is normal. You need to install manually.
Instructions
Follow the instructions below to install.
STEP 0) First, download the extension by choosing thebutton.
STEP 1a) Even though you got that yellow bar, the file still downloaded. Check your downloads folder.
STEP 1b) Now open up your Extensions page. It's located at chrome://extensions
You can copy and paste chrome://extensions into your URL bar,
or you can go to Tools > Extensions in your Google Chrome menu.
STEP 2) Then, just drag the file into the Extensions page and click OK button. That's it!
See the picture below: