Hi CCarroll The Not Junk button should only appear when you are looking at a message that has already been marked as Junk. Can you confirm you are in the inbox, and that the message has not been marked Junk? Note that there is a shortcut to mark as junk - hit letter j (lower case). This can happen by mistake if the user thinks they are in reply/forward/edit mode. Also if you have 'Enable Adaptive Junk Mail Controls' turned on Thunderbird should be trying to identify junk messages and setting them to Junk for you. More information on 'junk' in Thunderbird here https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages I hope some of this may help you! Agnes