If you find two different icons for the same program are pinned to your PC's or laptop's taskbar, it is probably due to an update to the program concerned. Our Helproom Editor explains how to remove duplicate icons from your taskbar.
Should you find in your taskbar two icons for just the program, follow our Helproom editor's advice
QUESTION A Mozilla Thunderbird icon is pinned to my Windows 7 Home Premium taskbar for easy access. Following a recent update, clicking this icon results in a second Thunderbird icon appearing alongside it, which disappears when I close the program. I've tried removing and re-adding the icon, but still two appear. How can I make things tidy?
HELPROOM ANSWER This is simple to fix. The original version of Thunderbird installed on your machine has a different name to the version with which it was recently updated. Windows isn't treating them as the same program, which is why you have two Thunderbird icons. (A similar fix will work for any duplicate icons.)
Launch Thunderbird using the original taskbar icon. Right-click the second icon that appears and choose 'Pin this program to taskbar'. Next, right-click the original Thunderbird icon and select 'Unpin this program from taskbar'.
You should find only one Thunderbird icon is visible the next time you launch the email client. See also: How to recover deleted emails and
Make sure there are no duplicate entries in your PC's taskbar.