Zotero Firefox Connector

Firefox just disabled my Zotero connector because 'it could not be verified.' This is a new development from Mozilla. Is there a connector revision that will soon be available? I'm currently running 5.0.66. I tried downloading 'Firefox Connector' but got the message that the file was corrupt. ??
Karl Hunt

Proxying The connector now supports proxy feature present in Z4FX. A relevant section has been added to the preferences page: Upon proxy detection standard browser notifications are displayed: Fi. Chrome, Firefox, and Safari extensions for Zotero. Contribute to zotero/zotero-connectors development by creating an account on GitHub.

  • Received message:
    Zotero Connection could not be verified for use in Firefox and has been disabled.
  • Looks like a temporary problem from Mozilla affecting all Firefox extensions. They're working on it:
  • I only found this out when I needed to index a key reference in Firefox. For now I have to go the manual root or consider another browser. Is Zotero working on resolving this matter with Firefox soon?
  • There's nothing we can do about this. This is affecting every single Firefox extension, so Mozilla is obviously trying to fix it as soon as possible.
    In the meantime you can save to Zotero via the Zotero Connector in another browser, download a PDF directly and let Zotero try to retrieve metadata, use Add Item by Identifier, or use https://www.zotero.org/save to save to your online library and sync.
  • Same problem. Thanks dstillman, I was getting crazy.
  • edited May 4, 2019
    This is all over the internet news and technology sites. Not Zotero specifically but all plug-ins. Mozilla said, according to the reports, that the problem is in part caused by an unexpected key certificate expiration.
    From TechCrunch
    ...the sudden failure is due to a code signing certificate built into the browser that expired just after 5 PM (or midnight on May 4th in UTC time)....
    Because the glitch stems from an underlying certificate, re-installing extensions won’t work — if you try, you’ll likely just be met with a different error message. Getting extensions back for everyone is going to require Mozilla to issue a patch....

    Other sites report that Mozilla expects to issue the update within a very few hours.
  • I have this problem too. Firefox is blocking Zotero lots of other reliable verified add-ons right now. It is really annoying!
  • Yes, everybody using Firefox is currently facing this problem, and there is nothing Zotero's developers can do. No need to write 'I have this problem too' over and over.
  • Update from Mozilla:
    Update: We have rolled out a partial fix for this issue. We generated a new intermediate certificate with the same name/key but an updated validity window and pushed it out to users via Normandy (this should be most users). Users who have Normandy on should see their add-ons start working over the next few hours. We are continuing to work on packaging up the new certificate for users who have Normandy disabled.
  • Nice to know that it is a general problem, so it will be fixed soon I hope.
  • Normandy is on by default. It's a way for Firefox to change settings without needing to install a new update.
  • I needed to change some privacy settings in Firefox (allow Firefox to install and run studies) to get the zotero connector to work again.
    This page helped me to find the right settings: https://support.mozilla.org/en-US/kb/add-ons-disabled-or-fail-to-install-firefox
    Very happy to be able to use Zotero with Firebox again!
    @Zotero team: Thanks for your great work!
  • Mozilla has now pushed out new versions of Firefox that fix this for all users:

The Zotero Connector browser extensions allow you to add items to your Zotero library with the click of a button in Firefox, Chrome, or Safari. This page describes the preferences for the Zotero Connectors. You can access the preferences by right-clicking (Firefox/Chrome) or clicking-and-holding (Safari) on the Zotero save button and choosing “Preferences”.

General Preferences

  • Zotero Status:

    • Whether the Zotero Connector can connect to the Zotero desktop client. If the Connector reports that Zotero is unavailable, see Zotero Unavailable.

  • Save to Zotero.org:

    • When the Zotero desktop client is closed, the Zotero Connector will save directly to the zotero.org servers. These settings let you reauthorize your broswer to save to your zotero.org account or clear your account credentials. You can also control whether PDF attachments and web page snapshots are automatically saved when importing to zotero.org.

  • Automatic File Importing:

    • By default, the Zotero Connector will offer to import RIS, BibTeX, and Refer/BibIX bibliographic files when you open them in your browswer. You can disable this feature or manage the sites from which data is imported here.

Proxies Preferences

Many institutions require you to sign-in to a proxy system to access electronic resources while you are off-campus. The Zotero Connector can make this more convenient. When it detects that you are using an institutional proxy to access a particular site, it will ask if you want to remember it in the future. If you agree, Zotero will automatically use the proxy for matching URLs in the future. You should be routed through the proxy login site if you're not already logged in, then you can access the database as you normally would.

Zotero users can use the proxies feature without ever looking at this preference tab. By default, Zotero will prompt you to store the proxy and then route you through the proxy automatically and without further input.

ZoteroZotero firefox connector

Zotero proxy redirection is not available in Safari.

The Proxies preferences allow you to adjust the following options:

  • Enable proxy redirection

    • Zotero's proxy redirection is enabled by default. Uncheck this option to disable proxy redirection. You can do this temporarily and your proxy settings will remain saved. Do not use this option if you no longer have access to the saved proxies. In that case, delete those settings by selecting them in the “Configured Proxies” box and pressing the minus (-) button below it.

  • Show a notification when redirecting through a proxy

    • By default, Zotero will show a temporary banner at the top of your browser when it redirects through a saved proxy. Uncheck this box to disable this notification.

  • Automatically detect new proxies

    • By default, Zotero will automatically detect when you visit a page through an institutional proxy and offer to remember the proxy the next time you visit the website. Uncheck this box to prevent Zotero from prompting you to store proxies it detects.

  • Disable proxy redirection when domain name contains

    • Typically you won't need to use a proxy when you are connected to the internet through your institution’s network. This option automatically disables Zotero's proxy re-direction when the domain of your internet provider contains the given string. In the United States, “.edu” (the default setting) will usually work. In other countries you will have to find out your institution's domain name.

    • This option is disabled by default. This option is only available when the Zotero desktop client is open.

Configured Proxies

When Zotero automatically detects and saves institutional proxies, they will be stored here. You can remove stored proxies by clicking the minus (-) button below the list. If you are having issues with a proxy, try to remove it from the list and re-add it by visiting the site and letting Zotero automatically detect the proxy settings again.

Zotero Firefox Connector Download

You can manually add proxies by by clicking on the plus (+) button. From there, you can specify the URL of the database being accessed under hostname and the URL scheme of the proxy. You can add/remove additional URLs to redirect through a single proxy by clicking on the plus (+) and minus (-) buttons below the Hostnames list. You can also enable/disable automatic association of new hostname URLs with a proxy server.

Some proxy servers require hyphens in proxied hostname URLs to be converted to dots. Check the box for this option if this is the case for your proxy server.

If you are having trouble accessing a site due to Zotero proxy redirection functionality, see Proxy Troubleshooting.

Advanced Preferences


These preferences are used for reporting errors and troubleshooting information to the Zotero developers.


  • Report Errors: If you are having a problem using the Zotero Connector, use this button to submit an Error Report ID to Zotero, then post to the Zotero forums. See Reporting Problems for instructions on how to submit helpful error reports.

  • Debug Output Logging: To help diagnose a problem, the Zotero developers may ask you to submit a Debug Log ID. This is different from an Error Report ID above. To submit a debug log, check “Enable Logging”, then complete the sequence of steps neeeded to produce your error. Then, click “Submit Debug Report” and post the Debug ID number to the Zotero forums. Try to avoid performing unrelated actions when making a debug log.

  • Translators: Zotero will automatically check for and install updated translators. You can manually check for updates here. By default, the Zotero Connector will report broken site translators to zotero.org. This helps Zotero to keep the Zotero import process working smoothly on sites across the Web.

  • Advanced Configuration: The Config Editor options are not useful for general troubleshooting and should only be used if instructed by the Zotero developers.