LibreOffice was unable to find a working e-mail configuration

Hi,

I use LO, windows 8.1, thunderbird but since upgrading to LO 4.3.1 I can not send documents via email with the button “Document as email” from writer and calc. I get “LibreOffice was unable to find a working e-mail configuration”. Thunderbird is set as default app and similar buttons work from firefox and MS office.

It appears to be connect to avast virus scanner: when I switch of “file system shield” in Avast, it all works.

Any suggestions?