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can't enable or re-install Avira Browser Safety (unsigned) add-on in FF v43.0

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Firefox has automatically (and without asking) disabled the Avira Browser Safety add-on after my upgrade to v43.0. It refuses to allow me to re-enable it. I then uninstalled and attempted to re-install it, but that too is disallowed -- regardless of whether I have the xpinstall.signatures.required flag set to true or false.

Is there another way I can get this add-on re-installed, or does Firefox simply no longer allow unsigned add-ons as of v43.0? (If the latter is the case, this is unwarranted and unduly paternalistic behaviour, in my opinion; the user should have the last word on what can and cannot be added on.)

Firefox has automatically (and without asking) disabled the Avira Browser Safety add-on after my upgrade to v43.0. It refuses to allow me to re-enable it. I then uninstalled and attempted to re-install it, but that too is disallowed -- regardless of whether I have the xpinstall.signatures.required flag set to true or false. Is there another way I can get this add-on re-installed, or does Firefox simply no longer allow unsigned add-ons as of v43.0? (If the latter is the case, this is unwarranted and unduly paternalistic behaviour, in my opinion; the user should have the last word on what can and cannot be added on.)

Chosen solution

I did give it a try and I can see the issue.

For security purposes, you cannot install unsigned extensions from any website. Instead, you will have to do the following:

  1. Go to the Avira Browser Safety website
  2. Right click the Add To Firefox button
  3. Click Save Link As..." to save the XPI file to your hard drive
  4. Go to the Firefox addons manager
  5. Click the gear
  6. Select Install addon from file
  7. Open the downloaded XPI file

This should install the addon correctly. Sorry if this is difficult or inconvenient.

Note: You may have to restart Firefox for the addon to be installed correctly.

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All Replies (6)

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You can disable addon signing by doing the following:

  1. Type about:config into the address bar
  2. Click the understand button
  3. Locate the xpinstall.signatures.required boolean
  4. Change the value to false
  5. Go to the addon manager
  6. Enable all desired addons

Note: You may need to restart Firefox for changes to take effect.

You can refer to this Mozilla support article for further information:

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Wesley, thanks -- your procedure works fine for re-enabling the add-on (as I've determined on a second machine configured similarly to the first one I tested on). However, it still won't allow me to re-install the add-on once it's been uninstalled. Any ideas on the latter?

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Seçilmiş Həll

I did give it a try and I can see the issue.

For security purposes, you cannot install unsigned extensions from any website. Instead, you will have to do the following:

  1. Go to the Avira Browser Safety website
  2. Right click the Add To Firefox button
  3. Click Save Link As..." to save the XPI file to your hard drive
  4. Go to the Firefox addons manager
  5. Click the gear
  6. Select Install addon from file
  7. Open the downloaded XPI file

This should install the addon correctly. Sorry if this is difficult or inconvenient.

Note: You may have to restart Firefox for the addon to be installed correctly.

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Also, please note that you can delete the downloaded XPI file from your hard drive once the installation has successfully completed.

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Wesley, you are THE MAN! Worked like a charm. Many thanks!!!

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No problem. Glad that I could help you. Thanks for contacting the Mozilla support team and we hope that you will continue to enjoy browsing the web with Firefox.