I've been using global extensions for a few years now. Once upon a time they would not work for me and I shared that experience:
Firefox and Global Extensions
I have not tried experimenting in this area in a long time. Although now I keep the DOM Inspector extension installed, I still refuse to install the talkback extension. I detest anything --- anything --- that evenly remotely smells of phone home regardless of intentions. I no longer have issues with installing extensions despite the absence of the talkback extension. However, I have not tried to perform a full clean install in a long time. I've had the same Firefox profile for several years now. Perhaps the old problem was fixed along the way, perhaps the problem was related only to the DOM Inspector extension, perhaps the problem remains. I don't know. Understand that the original essay was written back in the days of Firefox 1.5.x.
In that essay I mentioned the permissions problem. I suspect most GNU/Linux users do not delete the default Firefox extensions (DOM Inspector, Talkback), but the permissions issue is overlooked by many people. The problem does not occur in Windows because most users have full administrative permissions there, even when they install extensions globally. I suspect this is why some people report no problems with global extensions and some do --- different operating systems and different file permissions. I installed all my extensions globally in my NT4 box for many years and never had a problem. When I started using Slackware more often a few years ago and tried the same thing I discovered some of these quirks.
Another caveat is that many extensions remain compatible with each minor Firefox release but they get disabled easily. I hate developers who try to outguess me and protect me from myself. I wish they'd leave the extensions alone but no, they don't. There is a prefs.js setting to disable compatibility checking (
extensions.checkCompatibility) and I have that set to false these days. The important trick is to edit each extension's install.rdf file and change the
<em:maxVersion> directive to
2.0+ or
2.0.0.*.
But even that is insufficient. After editing the install.rdf, the profile extension.rdf file might contain a Disabled directive for an extension if compatibility checking is enabled. Delete that directive otherwise the extension will not work.
Yet that still might not prevent an extension from loading properly. These days when I update Firefox, before I start the new version, I manually edit my user.js file to the new version at both
extensions.lastAppVersion and
browser.startup.homepage_override.mstone. If the former option is set to the previous version of Firefox, then even if extensions.checkCompatibility is set to false, Firefox will immediately check all extensions and disable them. The 2.0+ and 2.0.0.* install.rdf trick in install.rdf will avoid problems, although the pompous automatic checking is frustrating. If the mstone version is incorrect, Firefox immediately pompously connects to the Mozilla home page.
The NoScript extension --- valuable in every way, is another self-minded example in that if the version number in prefs.js is different from the actual version, the extension automatically phones home and downloads the NoScript home page. So when I update that extension I again manually edit my user.js file (
noscript.version) before starting Firefox.
Currently I'm running 2.0.0.16 with all extensions installed globally. I have the following installed:
Diggler
FirstField
JavaScript Options
MIME Edit
NoScript
Open In Browser
Paste and Go
Prefbar
Read Easily
Searchbar AutoClear
TabMix Plus
Text Link
Zoomy
The most recently added extension was the videodownloader and guess what? After I installed the extension my normal user account could not use the extension. The default permissions were 400 rather than 644. So do check all the extension file permissions.
But somewhere along the updating from 2.0.0.14 to 2.0.0.15 or 2.0.0.16, videodownloader stopped working.
The nonsense continues in other ways. After I updated from 2.0.0.14 to 2.0.0.15, the prefbar extension stopped working. Although I had been using version 3.3.4 for a long time, I was forced to update that extension to version 4.1.1. I tend not to update extensions based loosely upon the old adage that if it ain't broke don't fix it.
I empathize with your situation. In certain ways, Firefox is a nightmare to maintain.
I hope some of this information helps.
