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Error: "FT DeepDark 11.3.1 could not be installed because Firefox cannot modify the needed file." What does this mean?

  • 2 replies
  • 4 have this problem
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  • Last reply by cor-el

RameyT53
RameyT53
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In an earlier version (Firefox v.31) on this, and (presently) on two other PC's, I was/am able to run add-on FT DeepDark 11.3.1 without any problems. It was only recently - after updating to v.32.0.3 on this PC that this situation started. The PC in question is a Dell Dimension 8400 Intel P4 running Windows 7, though I'm thinking it may have something to do with the newer version of Firefox. Could anyone help me with this? I like this add-on because it is easier in my eyes when browsing the internet. Thanks

PS: Attempted to install the troubleshooter, and again I received a similar error: "Troubleshooter could not be installed because Firefox cannot modify the needed file."

In an earlier version (Firefox v.31) on this, and (presently) on two other PC's, I was/am able to run add-on FT DeepDark 11.3.1 without any problems. It was only recently - after updating to v.32.0.3 on this PC that this situation started. The PC in question is a Dell Dimension 8400 Intel P4 running Windows 7, though I'm thinking it may have something to do with the newer version of Firefox. Could anyone help me with this? I like this add-on because it is easier in my eyes when browsing the internet. Thanks PS: Attempted to install the troubleshooter, and again I received a similar error: "Troubleshooter could not be installed because Firefox cannot modify the needed file."

All Replies (2)

NoahSUMO
NoahSUMO
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This error has been reported before in this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=730040#c21

Please read that bug I linked you to and let me know if the last comment in the bug solves your problem. Apparently the problem is about the addon .xpi file being read-only. Try right-clicking it, going to Properties and unchecking the "Read-only" attribute box at the bottom of the dialog. Click Apply, then OK.

Modified by NoahSUMO

cor-el
cor-el
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You may also have to force Firefox to unpack the extension by toggling the extensions.alwaysUnpack pref to true on the about:config page.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.