''re :I wonder if my copy of Thunderbird has been compromised or the Thunderbird server has been compromised. '' There is no such thing as 'Thunderbird server' for anyone using a free Thunderbird program. Emails are received into the server that handles your emails. That might be an email address provided by your Internet Service Provider or maybe a free email address such as those provided by gmail or it may be an email address you have because you have purchased a domain etc. Thunderbird simply accesses the server and downloads whatever is in the server Inbox. The server is set up to receive whatever is sent to it. You are paying that company to accept emails sent to your email address. Usually, servers have their own Spam filters to detect spam and then server usually puts those emails into the server Spam folder. You would only be able to see them if you created an Imap mail account. In webmail account, you can usually set up what is deemed as safe or unsafe sender, so server auto filters those into the Spam folder. In Thunderbird, 'Account Settings' > 'Junk Settings' for each account - you can set up and train the Thunderbird Junk filter to recognise what you deem as Junk or Not Junk. '''Why are you getting spam in the first place:''' Your email address is known by nefarious people and they are block sending spam mail to your email address. The Source View of your email should offer information on the initial source of sender maybe it includes an IP address. The top Received by will your server and the one closest to the From, Subject, To, Date headers will be the first server to receive the email. Maybe your email address is displayed on some website so any search bot might discover it. Advice on checking the date issue: You need to determine whether Thunderbird is involved in altering anything. Process: I would suggest that you check the webmail account first thing in the morning before you start up Thunderbird. You would need to logon and check the webmail account to see if it displays all the same date/time for new spam mail. Make a note of the date/time or take a screendump image of server data. Then you will know whether the date time is all the same on server '''''before '''''it gets downloaded to Thunderbird. Once you have checked the server, start up Thunderbird, let it do the downloaded and notice if it displays same date/time as server when emails are downloaded.