Hmm, if Firefox's Master Password feature is interfering, you could temporarily turn off Firefox's Password Manager so that doesn't kick in. (Or permanently if you plan to replace it with LastPass anyway.) You can do that on the Options page:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the search box at the top of the page, type login and Firefox should filter to the "Logins & Passwords" setting.

Then uncheck the box for "Ask to save logins and passwords for websites"

Any improvement?

Hi- I tried what you told me to do & am getting the same scenario when I try to create an account. Attached are two screen shots (in the order I see them). What else could I try?

Thanks, I didn't realize LastPass uses the phrase Master Password, too. Hopefully someone familiar with the program with have further suggestions, or perhaps LastPass support will recognize the problem.

Firefox says the file is corrupt and will not install it. Ever since the update, this browser has been nothing but issues...and slow. Been using LastPass for years with this browser with issues from time to time. Not sure where it's coming from. Please fix it.

Hi saettone, you are probably suffering from a new issue that arose a few hours ago.

A critical Add-on-related certificate expired (which obviously should not happen). The Add-ons team is working on a fix for this. Official updates are expected to be posted here:

https://discourse.mozilla.org/t/certificate-issue-causing-add-ons-to-be-disabled-or-fail-to-install/39047

Currently, the only workaround is to set your system clock back (for example, if your date is May 3, set to May 2; if your date is May 4, set to May 3). You might have to reinstall extensions after that, or maybe Firefox will detect the difference at your next shut down/restart. Changing the date may have other consequences, so I understand this option isn't ideal.

Thanks for the update

Mozilla has rolled-out a fix for this. The fix will be automatically applied in the background within the next few hours, you don’t need to take active steps.

In order to be able to provide this fix on short notice, they are using the Studies system. You can check if you have studies enabled

1. Go to [=] > Options > Privacy & Security.
2. Make sure Allow Firefox to install and run studies is check marked.

I you had it disabled, you can disable studies again after your add-ons have been re-enabled.

They are working on a general fix that doesn't need to rely on this and will keep you updated.

Thanks for all replies. I was able to create an account via my Internet Explorer 11 Browser without any problem. I was then able to use Last Pass in Firefox using the add-on. Seems to work fine. I highly suggest to anyone with a lot of passwords to install and use this add-on.