firefox add-ons.jpgEver since we launched the CyberSearch extension I’ve been getting a ton of emails with recommendations on what I can do to make it better, and alongside those emails are also a few dozen from people who are having troubles trying to install it. What happens to them, and I’ve had this happen to me before, is they are prompted with this warning when trying to install the extension:

Firefox could not install the file at [URL] because: Invalid file hash (possible download corruption) -261

Believe it or not this has been a known problem for quite some time, and there are a couple of different things you can try to circumvent the problem.

  1. Clear your cache. Go to Tools -> Options -> Advanced -> Network / Offline Storage -> Clear Now and then try reinstalling the extension.
  2. Enable third-party cookies. A few commenters (thanks Clark!) have pointed out that enabling third-party cookies in Firefox is also something you should do to get around the error message. To do this go to Tools -> Options -> Privacy and check the Accept third-party cookies box.
  3. Manually install the extension. The easiest way to do this is to just download the extension in another browser, and then drag the downloaded file into the Firefox window. This should initiate the installation process.
  4. Suspend ThreatFire. I’m adding this one to the list because several of our commenters (thanks Sunny!) have pointed out that ThreatFire could be one of the reasons that extensions won’t install. Temporarily suspending ThreatFire should solve the problem.
  5. Temporarily disable your antivirus. When all else fails the culprit could be that your antivirus application is preventing the installation of the extension. This is kind of a last resort, and not something that I really recommend doing.

Again, I apologize for those of you having issues installing the extension, but there is a light at the end of the tunnel. Once we manage to get enough (hopefully positive) reviews of the extension we will be able to get CyberSearch out of the experimental stage. From what I’ve read after that happens the “invalid file hash” errors shouldn’t really happen anymore. So if you’ve got a spare second go drop by the Mozilla site and leave a review for our extension.