Bug 531088: ‘Need warning and UI for destructive POP3 default setting’ has been around since the Thunderbird 3 days (November 2009) and is still listed as one of the two critical bugs in the Daily Builds threads on the mozillaZine Thunderbird Builds forum. Here is a brief summary of this bug (issue):

By default when a new POP3 account is setup in Thunderbird 3 and newer, the server settings are such that messages will be removed from the server after 14-days from when they are downloaded. Plus, no where during the setup process of their account in Thunderbird are the users warned about this. The user would have to manually go into Tools > Account Settings… > then click on Server Settings for the specific email account to see and modify this setting.

Default setup starting with Thunderbird 3 has the Leave messages on server box checked.

Now, I have used Outlook/Outlook Express for many years prior to Thunderbird where the default setting is to remove the messages as soon as they are downloaded. Further, from my days prior of walking people setting up various email clients the default behavior for the majority of those clients is to remove the message after downloading.

So then, what’s the big deal? It could be said Thunderbird’s default setting could be problematic in that is unneedingly cluttering the user’s mail server with messages that have already been downloaded. But, that is not what the person who filed this bug considers to be destructive behavior. It is the fact the user is unaware their messages are going to be removed from the server after 14-days.

There has been about 50 comments on this bug, most of which were posted on or before July 2010. Many of those were arguing about ‘proper’ POP behavior versus IMAP. Again, the main issue seems to be users are not aware that their messages will be removed from the server at 14-days, even though most other email clients by default don’t retain the messages on the server at all.

For most people having the messages automatically removed from the sever upon download (again default behavior for most email clients including Outlook/Outlook Express) is fine. Those (such as myself for 1 of my 3 accounts) who want to have the messages left on the sever (so they can be picked up by another client on another machine or device or viewable via web-mail) as well should know already that they will need to make a tweak in the server settings. This is especially true if they have been using Outlook/Outlook Express.

The assumption I get from reading the description of the bug as well as the first few comments is users who have never used an email client before are going to download, install and setup Thunderbird then log on to their mail server 15-days later and discover their messages are gone.  The problem I have with is assumption is the part about people who have never used an email client before. From my experience most people who are setting up Thunderbird have already used another email client in the past and since the majority of those clients automatically remove the messages from the server once downloaded would expect Thunderbird to do the same.

I brought up this issue in my support forum. While only few people responded to my poll question if they had used another email client prior to Thunderbird, all of them had used another client prior. One person even commented they had no expectation for the email client to leave a copy of the message on the server unless they made that change otherwise.

Given this bug has been open for the past year and half, plus with the exception of one (very good) comment in February the last series of comments were in July of 2010, makes me think that most people don’t think this is that big of an issue. That very good comment was a suggestion that once the account is created, the user is taken to the Sever Settings section on the Account Screen. At least there they will see that the setting screen and will (hopefully) see Thunderbird is set to remove the messages after 14-days.