This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Cari Bantuan

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.

Pelajari Lebih Lanjut

Can't reinstall add-on after downgrading

  • 11 balas
  • 1 memiliki masalah ini
  • 1 kunjungan
  • Balasan terakhir oleh ram116

more options

Hi,

I'm trying to downgrade back to Firefox 56 after updating to Quantum, because there is no FTP add-on and I want to keep using FireFTP. However, now that I've downgraded, I cannot reinstall FireFTP because it's unsigned, meaning that not only can I not keep on the way I'd been keeping on, I also can't get all my login data from the FTP client in order to apply it to another client. When I try to install the .xpi from the developer's github, I get "Firefox has prevented this site from installing an unverified add-on."

How can I install this add-on, or failing that, at least get all my data from it?

Thank you!

Hi, I'm trying to downgrade back to Firefox 56 after updating to Quantum, because there is no FTP add-on and I want to keep using FireFTP. However, now that I've downgraded, I cannot reinstall FireFTP because it's unsigned, meaning that not only can I not keep on the way I'd been keeping on, I also can't get all my login data from the FTP client in order to apply it to another client. When I try to install the .xpi from the developer's github, I get "Firefox has prevented this site from installing an unverified add-on." How can I install this add-on, or failing that, at least get all my data from it? Thank you!

Semua Balasan (11)

more options

On Friday, May 3rd, 2019, we became aware of an issue with Firefox that prevented existing and new add-ons from running or being installed. We are very sorry for the inconvenience caused to people who use Firefox.

Mozilla has released updates to resolve the issue. See the article Add-ons disabled or fail to install on Firefox and this Mozilla Blog post for more information.

Although the issue has been fixed on the recent version of Firefox, it may still take some time to get a working fix for the older (and unsupported) versions. There are some steps at the bottom of the blog post linked above to apply a hotfix to your browser.

Hope this helps.

more options

Thank you, it seems like the studies are already enabled.

more options

Hello ram116,

This extension was just released and should solve the problem :

https://addons.mozilla.org/en-US/firefox/addon/disabled-add-on-fix-52-56/

more options

Still the same response, I'm afraid :(

If it's not possible to reinstall the add-on, is there any way for me to recover the stored credentials?

more options

Did you previously take any action to get the new certificate to replace the expired certificate?

Do you see the certificate in the Firefox Certificate Manager?

Are there messages in the Browser Console about this extension if you check this after a startup?

You can check in the Certificate Manager whether you have the new intermediate certificate installed. You can find it under the Authorities tab.

  • Options/Preferences -> Privacy & Security
    Certificates: View Certificates

Scroll down to see if you can locate this entry:

more options

No, no previous action; I'm not familiar with how that works. This particular add-on is no longer in the add-on shop (it's FireFTP and needs to be obtained from the developer's git these days) but it had been working just fine before I updated. No console messages, I do see that Mozilla certificate.

more options

The FireFTP extension isn't signed, so you would have to disable extension signing to be able to install this Legacy extension.

This pref sets whether honor extension signing and you would have to disable this security feature to be able to install this extension

  • xpinstall.signatures.required = false

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.


You can check for problems with the extensions registry files in the profile folder.

Try to to reset the extensions registry and rename extensions.json (extensionsOLD.json) and rename/remove previously used extensions files like extensions.ini and extensions.sqlite when present and rename/remove compatibility.ini in the Firefox profile folder with Firefox closed.

New files will be created when required.

See "Corrupt extension files":

If this didn't help then delete add-ons.json and possibly prefs.js in case there is a problem with preferences.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

more options

You are better off using the current Firefox and using a proper FTP client for anything FTP.

A FTP client to consider is the open-source FileZilla FTP client that has been around for a long time. It has no relation to Mozilla as some mistaken due to zilla in name.

https://filezilla-project.org/

more options

Hello, sorry for the delayed response, I had some time off.

@cor-el I tried your suggestions of unchecking signing and of renaming the extensions and compatibility files; this was unsuccessful.

@James I'm trying to install FileZilla and having some trouble. Hopefully our IT can sort that out, but as I said earlier I'm still concerned that I may not be able to recover any of my logon data from FireFTP, even if I do need to begin using another FTP client. Any ideas for recovering my data from this application?

more options

You can do a search in the profile folder for two files.

fireFTPsites.dat
fireFTPprograms.dat
more options

fireFTPsites.dat has most of the data, but not passwords.