Can't install add-ons in Firefox 4 "[add-on] could not be installed because Firefox could not modify the needed file."
I have tried to install add-ons for Firefox 4, but have been unsuccessful.
If I try to install from within about:addons, the add-on will download but then the installation bar will not change. If I try to install from addons.mozilla.org, the add-on downloads but then I get a message from the site information box (alongside the address bar) which reads, "[add-on] could not be installed because Firefox could not modify the needed file."
If I try to install any other add-ons after this, I get an error.
I am running Ubuntu 10.10 on a Toshiba Satellite U400.
About config variables xpi:enabled = true.
Réiteach roghnaithe
I'm having this problem. I'm also running 32-bit Ubuntu 10.10 and Firefox 4.0 (Canonical version 1.0). When I try to install the Greasemonkey addon (and other addons), it downloads, but the install progress bar stays at 0%. I also can't cancel the install. If I try I get the error:
Error: Cannot cancel install of https://addons.mozilla.org/firefox/downloads/latest/748/addon-748-latest.xpi?src=addondetail from this state (5) Source File: resource://gre/modules/XPIProvider.jsm Line: 5168
When trying to install I get this error in the error console:
Error: this.installLocation is undefined Source File: resource://gre/modules/XPIProvider.jsm Line: 5751
I read on the Firefox troubleshooting page that xpinstall.enabled needs to be set to true in config:about, but it didn't exist in my config list, so I tried adding it, but it made no difference.
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Réiteach Roghnaithe
I'm having this problem. I'm also running 32-bit Ubuntu 10.10 and Firefox 4.0 (Canonical version 1.0). When I try to install the Greasemonkey addon (and other addons), it downloads, but the install progress bar stays at 0%. I also can't cancel the install. If I try I get the error:
Error: Cannot cancel install of https://addons.mozilla.org/firefox/downloads/latest/748/addon-748-latest.xpi?src=addondetail from this state (5) Source File: resource://gre/modules/XPIProvider.jsm Line: 5168
When trying to install I get this error in the error console:
Error: this.installLocation is undefined Source File: resource://gre/modules/XPIProvider.jsm Line: 5751
I read on the Firefox troubleshooting page that xpinstall.enabled needs to be set to true in config:about, but it didn't exist in my config list, so I tried adding it, but it made no difference.
I did some further troubleshooting and realised that the problem was that firefox could not install add-ons because the profile folder was read-only; ie. it needed to be running as root in order to be able to install any extension. So, i ran firefox from the console as root, and everything worked fine. However, as i didn't fancy having to log in as root every time, i figured there had to be a better solution.
In the end, after some trial and error, i uninstalled firefox, then removed every mozilla and firefox-related file i could find on the hdd. I then updated the stable mozilla repositories and did a fresh install of firefox 4 in the system, instead of ober the previous install of 3.6. This seems to have worked as i have had no further problems wth ff4.
Just an update - I renamed my /.mozilla directory to another name, so effectively there was no .mozilla directory anymore. When I started Firefox, everything was fine, I could install add-ons.
Unfortunately I now have to restore bookmarks, addon settings, cookies and all other information that was in my old .mozilla directory.
Yes, I had to reinstall everything too. Although my bookmarks were already in threw cloud, and the add-ons were mostly functional ones which now exist in threw new UI, so it wasn't such a hassle for me.
solution: $sudo chmod -R a+r+w+x ~/.mozilla/
I'm having the same problem running OS X version 10.6.7. It would be really helpful to know what the "needed file" is.