Hi lisaev, I was a bit reluctant to post as I do not have a solution, and it may put others off from posting. (Post again to bump the thread if it goes a few days with no other answers) I am not even sure what that does.

addons.mozlla.org generates a warning anyhow, stupid as it seems, apparently due to a longstanding bug.

I am not sure other places are hard blocked. For instance this will install after a warning but is not whitelisted

• http://mozilla.github.io/shumway/extension/firefox/shumway.xpi (from http://mozilla.github.io/shumway/ )

Hi John99,

Thanks for you reply. However, I don't understand what you mean by "hard blocked". I think if an addon install _after_ a warning, it's expected.

My problem is _not_ that I can't install add-ons (I can). The issue is that I can't clear the whitelist of sites that are allowed to install those without warning because this setting is simply not saved (it returns to a default after restarting FF).

This seems to be a bug in UI somewhere but I am hoping that I missed some setting (perhaps in about:config).

As a separate subject some specific add-ons are blocked to some degree.

• A explained in Why does Mozilla disable some add-ons from running in Firefox?
• Listed here https://addons.mozilla.org/en-US/firefox/blocked/

So some addons can be blocked from installing. That feature is controlled not from a whitelist but from a blacklist that ordinarily updates daily and is in a profile file blocklist.xul

Thanks for you reply. However, I don't understand what you mean by "hard blocked". I think if an addon install _after_ a warning, it's expected.

But if addons.mozilla.org already gives a warning what are you expecting to change. The other whitelisted site I see is marketplace.firefox.com and I am not sure that even offers anything to install on Firefox Desktop

I have tried with

• Preferences(Tools) -> |Security| [./] Warn ...[Exceptions]
  • I was able to delete both the listed items
  • They remained deleted on restarting

edit unable to reproduce (Modified February 3, 2015 12:12:11 AM BST by John99 ) Rather unexpectedly this resulted in me getting no warning and being able to install from mozilla.addons whereas the shumway.xpi also installed but gave a warning. Rather interesting given that I thought a long standing bug prevented us installing from mozilla.addons without generating a warning. I will have to look up that bug.

P.S. _{Bug 646602 - Installing add-ons from AMO should not invoke the security prompt}

I am unable to reproduce the download without security warning.

I have repeatedly & reproducibly removed the white list entries though.

The default entries in the white list are controlled by two prefs. If these prefs have the default value then those entries are created automatically if you open the exceptions window ("Warn me when sites try to install add-ons": Exceptions)

• xpinstall.whitelist.add (addons.mozilla.org)
• xpinstall.whitelist.add.180 (marketplace.firefox.com)

Clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, passwords, and other website specific data.