This is an issue with the Epson software or Windows, depending on exactly how you are doing the scanning. First things first, let's make sure that Windows has Thunderbird set to be the default e-mail program. If you are are using Windows 8 or 10: '''1.''' Type "default" into Cortana search, then click on the search result '''Default Programs'''. See my first screenshot below. '''2.''' Under Choose default apps, change the E-mail to Thunderbird.. '''3.''' Scroll down to the bottom of that window and click on '''Set defaults by app'''. '''4.''' You will now see a screen like my second screenshot below. Find and select Thunderbird, then click on '''Set this program as default''' on the right side. '''5.''' Click OK on that window, and close the other windows. If you are using Windows 7 (or earlier), then skip steps 1-3. To see the window in step 4, open the Control Panel, view it by small icons, then click on Default Programs, as depicted in my third screenshot below. Then continue on with the steps. If this does not resolve your issue, then the problem is probably with the Epson software you are using for scanning. Without being able to see that software and its settings, all I can do is say, "Ask Epson".