This URL will download latest version of the extension. Paste this newly formed URL in another browser like Firefox or IE. Now, you will have to put that extracted ID in the following URL: EXTENSION_ID%26installsource%3Dondemand%26uc Update: As some users have pointed out, going into Incognito Mode with Ctrl-Shift-N, loading the page of the extension in that mode and clicking on install then should also fix the issue.Then its ID is – mihcahmgecmbnbcchbopgniflfhgnkff I can't say what is causing this but if you run into the error, I suggest you check if you are signed in and if you are not, sign in to see if it fixes the issue on your end. I then signed in on the second Chrome browser and here too, the installation went through without issues. Signing out in the other browser and signing in again on the other hand let me download and install the extension just fine a second time. I tried it again in the second version of Chrome that I was not signed in and it failed again. Guess what, after signing in the installation went through without issues.

Last thing I tried, and that is one of the things that still puzzles me, is to sign in to a Google account. I tried a lot of things afterwards, clearing the cache, trying to find the download url of the crx file manually and all of that stuff. For one, they had a slightly different file size which is obviously a bad sign if it is the same file download.

The download directory was listing the crx file downloads, but attempts to install the extensions in Chrome revealed that they appeared to be corrupt. Turned out, I received the same error messages when trying to install extensions in the browser too. I fired up Chrome Canary, another version of Chrome that I use rarely to see if I was able to install extension in the browser. Somehow Chrome was not download an extension file, which do have the crx file extension, but something else. I did receive the same error message which puzzled me. Reloading did not fix the issue, neither did a restart of the browser, and next thing I tried was to install another extension from the official web store to see if it did install in Chrome. The message below that stated that the download was not a CRX. When I tried to install a Google Chrome extension in the latest dev version of the web browser I was notified that an error had occured.

Chrome crx download