Preferences error on Sending email

[grzz76]

Starting this afternoon, I've been receiving this error message on sending emails:

[Javascript Application]

Preferences error
ReferenceError: nsPreferences is not defined

However, my emails are going through, so it does not appear to be a fatal error. Any ideas on what is causing this? I haven't made any changes to any settings on Thunderbird.

Thanks.

Thunderbird 52.0.1
Windows 7

[DanRaisch]

Does the same thing occur if you launch the application in Mozilla Safe Mode? http://kb.mozillazine.org/Safe_mode

[grzz76]

Thank you. I narrowed it down to the extension WithAttach. I have removed it and everything is now fine!