Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

<Add-on> could not be installed because Firefox cannot modify the necessary file.

  • 1 reply
  • 10 have this problem
  • 1 view
  • Last reply by cor-el

switch
switch
more options

I see that for the issue:

<Add-on> could not be installed because Firefox cannot modify the necessary file.

The usual fixes include: - ensuring that xpinstall.enabled is set to true - ensuring that extensions.alwaysUnpack is set to true

What might be the non-usual fixes as I have set both to true and I still get the message above.

I have tried installing the <add-on> after I have set the values to true, then again after restarting my browser, then again after restarting my computer and finally tried creating a new profile and repeated each of the steps after setting the 2 preferences to true.

I see that for the issue: <Add-on> could not be installed because Firefox cannot modify the necessary file. The usual fixes include: - ensuring that xpinstall.enabled is set to true - ensuring that extensions.alwaysUnpack is set to true What might be the non-usual fixes as I have set both to true and I still get the message above. I have tried installing the <add-on> after I have set the values to true, then again after restarting my browser, then again after restarting my computer and finally tried creating a new profile and repeated each of the steps after setting the 2 preferences to true.

All Replies (1)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

Can you at least update to the latest Firefox 10.0.10 ESR version?

Firefox 10.0.x ESR:

So a new profile with no other extensions didn't work as well?

Which extension is causing this problem or can't you install any extensions at all?