Hi Rich, one possible reason for this is using a password manager add-on that doesn't want to to accidentally (ha ha) use the built-in password manager. Do you have any add-ons like that? Here's how to check:

You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. On the right side, find the "Manage Your Extensions" heading.

If there is at least one extension before the next heading -- "Recommended Extensions" -- please continue:

Then cast a critical eye over the list below that heading. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything password related here? Anything you do not remember installing or why? If in doubt, disable (or remove). For your privacy and security, don't let mystery programs linger here.

Was there anything relevant there?

You can't have multiple Password Managers enabled at the same time, if you have others like RoboForm or Trend Micro Password Manager, the builtin Firefox Password Manager will be disabled.

If you have the "Trend Micro Password Manager" installed, uncheck the password Protection box in its configuration or uninstall this application via the Windows Control Panel.

Thanks for the assistance. I disabled the Trend Micro toolbar extension and it now works.