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.

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

Cannot install Lastpass add-on

  • 5 majibu
  • 1 ana tatizo hili
  • 37 views
  • Last reply by FredMcD

more options

Since upgrading to FF42 (now on FF43) I haven't been able to install FF - either from the add-on tab or from lastpass's site. I have done a FF clean install; I have done FF refresh. I can install on Chrome without issue, but firefox is my preferred browser. I have contacted Lastpass and they have tried to resolve the issue, but it installs for them without issue. I am on Windows 7.

The attached powerpoints show the error messages. If I try from the add-on page, I get "There was an error installing lastpass". If I use the link lastpass provided (https://addons.mozilla.org/en-US/firefox/addon/lastpass-password-manager/) I get "LastPass could not be installed because Firefox cannot modify the needed file).

Since upgrading to FF42 (now on FF43) I haven't been able to install FF - either from the add-on tab or from lastpass's site. I have done a FF clean install; I have done FF refresh. I can install on Chrome without issue, but firefox is my preferred browser. I have contacted Lastpass and they have tried to resolve the issue, but it installs for them without issue. I am on Windows 7. The attached powerpoints show the error messages. If I try from the add-on page, I get "There was an error installing lastpass". If I use the link lastpass provided (https://addons.mozilla.org/en-US/firefox/addon/lastpass-password-manager/) I get "LastPass could not be installed because Firefox cannot modify the needed file).

All Replies (5)

more options

This will disable add-on signature enforcement; Enter about:config into your Firefox address bar Click the I'll be careful button Find xpinstall.signatures.required in the list Right click the preference Select Toggle until the value is false https://support.mozilla.org/en-US/kb/add-on-signing-in-firefox

https://wiki.mozilla.org/Firefox/AddOns/Status/Updates#Exec_Summary “Currently targeting Signing with no pref to turn off in Firefox 47”

more options

Thanks Fred - have just tried this but same result - still cannot install and throws the same error messages.

more options

Contact their support site for more help, or a reason for the error.

more options

I did - and they routed me here. They have no idea what is causing it.

more options

I've called the big guys to help you. Good luck.