Could you check your Message Filters, and in particular the After Sending check mark, as well as any rules involved in adding stars? You could also disable all or any of them to see if it makes a difference. Also, I think the Filter Log (if enabled) should tell you why the star was added.

If you don’t "trust" the filters or the above doesn’t help but you think filters may be related somehow, you could reset the filters by deleting or moving the file msgFilterRules.dat in your profile folder when Thunderbird is closed.

More info on message filters can be found here.

I tested this by removing the filter. However, the problem continued.

Is it more like an asterisk or is it a 5-pointed star? Is it in the star column or tucked in next to the subject? If you're not sure how to answer, maybe you could post a screenshot.

The asterisk-like symbol indicates an unread message which is perhaps a rational label for a message that's just appeared in the Inbox, whereas the star is a user-applied marker and therefore its spontaneous appearance would be slightly harder to explain. Certainly a filter is a possible culprit but you have to wonder why it just suddenly started doing its thing.

It is a star. It appears after a reply is sent from a particular mailbox. The reply appears without the star and then the star is added a second or two later. Indeed it is very strange that this behavior started after many years of normal performance.

_{(Please make sure to reply to helper’s suggestions and questions as good as possible.)}

Hence: - Are there any filters using the After sending check mark? - Apart from removing "the" filter, did you check or disable other filters, if any? - Did you try removing the msgFilterRules.dat file in your profile folder (when TB is closed)? - Did you check the Filter log to see what filter was applied? (That only indicates the filter name though, not the actions.) - Is it in the star column or tucked in next to the subject? (See here for an example of what a real star is, and just pressing "s" should toggle stars.)

Additionally: - Are you using any add-ons and if so, did you disable them manually or start TB in Safe Mode, either by holding the option key during TB startup (for Mac; shift on Windows) or by choosing Help > Restart with add-ons disabled ? - How did you set TB to save a reply in your inbox? Did you set it in Account Settings > Copies & Folders, top section (Place a copy in:) or using a filter? - Are you using one or more accounts, and are they POP or IMAP? - Are you using a Gmail IMAP account? If so, chances are the star is added by Gmail and then synced with Thunderbird, so make sure they do not get starred there.

Since you wrote "…and then the star is added a second or two later", this may indicate a relation to the Automatically mark messages as read setting in Preferences > Display pane > Advanced tab, which is unlikely. Try disabling that and see wat happens. You could also mark a message as unread manually and then as read again to see if a star is added.

So many questions! Answers below...

- Are there any filters using the After sending check mark? - NO - Apart from removing "the" filter, did you check or disable other filters, if any? - SEE NEXT ANSWER - Did you try removing the msgFilterRules.dat file in your profile folder (when TB is closed)? - YES - Did you check the Filter log to see what filter was applied? (That only indicates the filter name though, not the actions.) - YES, THERE WERE NO FILTER ACTIONS WHEN THE STAR WAS ADDED - Is it in the star column or tucked in next to the subject? (See here for an example of what a real star is, and just pressing "s" should toggle stars.) - IT IS A REAL STAR

Additionally: - Are you using any add-ons and if so, did you disable them manually or start TB in Safe Mode, either by holding the option key during TB startup (for Mac; shift on Windows) or by choosing Help > Restart with add-ons disabled ? - I USED IN SAFE MODE AND STAR WAS STILL ADDED - How did you set TB to save a reply in your inbox? Did you set it in Account Settings > Copies & Folders, top section (Place a copy in:) or using a filter? - THIS WAS DONE IN SETTINGS, NOT AS A FILTER - Are you using one or more accounts, and are they POP or IMAP? YES, USING MANY ACCOUNTS - ALL IMAP - Are you using a Gmail IMAP account? If so, chances are the star is added by Gmail and then synced with Thunderbird, so make sure they do not get starred there. - I CHECKED THIS. STAR IS BEING ADDED IN A GODADDY ACCOUNT, BUT I CHECKED THE ACCOUNT IN GODADDY AND THERE ARE NO FILTERS THERE DOING THIS. ALSO, I HAD NOT MADE ANY CHANGES TO THE ACCOUNT PRIOR TO THIS HAPPENING.

Since you wrote "…and then the star is added a second or two later", this may indicate a relation to the Automatically mark messages as read setting in Preferences > Display pane > Advanced tab, which is unlikely. Try disabling that and see wat happens. - THIS HAS ALWAYS BEEN DISABLED FOR ME. You could also mark a message as unread manually and then as read again to see if a star is added. NO IT IS NOT.

PROBLEM REMAINS.

If I understand this well, Thunderbird was set up to place a copy of a sent email message into the inbox for the Godaddy account.

- Are there any other accounts set up in a similar way? - Does a sent message also get starred in Thunderbird’s Sent folder, both for the Godaddy account and the other accounts? - Keep in mind the copy is a local copy and hence needs to be synced with the IMAP server when set. Does it get synced with the server anyway, i.e. do you see it in your inbox using webmail? If so, do they have stars there? - Could the issue be temporary, i.e. the stars in Thunderbird disappear after syncing?

In any case, you may want to check your synchronization settings for the account under its Account Settings > Synchronization & Storage > Advanced.

Now I won’t try to blame Godaddy rightaway, but one could imagine some (silent) implementation or other change at their end causing this - after all, the other accounts don’t suffer it. Looking at this support question and this mozillaZine topic, some weird things are happening with regard to Godaddy accounts, Thunderbird and stars lately. Also, I don’t think any starring at their end would necessarily mean this has to be done by a filter, but perhaps some other setting instead. The first thing I’d be interested in is not what adds them, but if and when stars ought to be synced, since you’re using IMAP. Next step is to switch it off, of course.

Depending on answers to the questions above, I would advise to remove the account in Thunderbird and re-add it (your account settings should be kept when uninstalling.) If that doesn't help or if you think the issue could be related to a Thunderbird update (which is possible, but some input is needed in order to call this a bug), please consider uninstalling Thunderbird and install a previous version that you did not experience the issue with, such as 45.0 or 45.2.0, assuming version 45.4 is installed. You could check Thunderbird’s Update log (Preferences > Advanced > Update tab > Show update history) to get an indication of the previous version, if unknown.

There is a possibly related bug 1284036 for read messages at Godaddy to be marked as unread after replying. I believe you when you said this is about real stars, but you will probably understand the thought of them being "new mail" symbols. ;)

Thank you for your continuing with me on this problem. Here are some more answers: - Are there any other accounts set up in a similar way? - YES, MOST OF THE OTHER 5 ACCOUNTS ARE SET UP THIS WAY, ONLY THE GODADDY ACCOUNT HAS THE "STAR" PROBLEM. - Does a sent message also get starred in Thunderbird’s Sent folder, both for the Godaddy account and the other accounts? - YES. AT SOME RECENT POINT IN TIME (POSSIBLY SIMULTANEOUSLY WITH THE RECENT THUNDERBIRD UPDATE) EVERY EMAIL EVER SENT FROM THIS ACCOUNT WAS STARRED - IT HADN'T BEEN STARRED BEFORE. - Keep in mind the copy is a local copy and hence needs to be synced with the IMAP server when set. Does it get synced with the server anyway, i.e. do you see it in your inbox using webmail? If so, do they have stars there? - YES THEY ARE ALL IN WEBMAIL AND THEY CARRY THE SAME STARRED STATUS AS IN THUNDERBIRD. - Could the issue be temporary, i.e. the stars in Thunderbird disappear after syncing? - UNFORTUNATELY NOT.

Again, these are real stars, not message read symbols. It only happens with the GoDaddy account. Once I unset the star they stay off. It is annoying but not debilitating. Given the depth and complexity of my mail system I am not going to attempt to remove the account or to revert to an earlier Thunderbird version. It is just not worth the trouble. Hopefully a future update to Thunderbird will eliminate the problem.

It seems obvious the stars get synced, but the question is into what direction, i.e. if they originate from Thunderbird or Godaddy. Hence I wonder: can messages get starred at Godaddy webmail even without Thunderbird being active (i.e. what is the reason), and then get synced in return? I couldn’t find any info other than this page about Message Marking. I know Gmail’s webmail does it sometimes even without using Thunderbird, but I never wondered why.

Although I do think copying an outgoing message to an Inbox is slightly uncommon, I won’t say there is no bug in Thunderbird. But instead, synchronization of stars themselves OR adding stars to synced messages to a Saved folder could also be a newly implemented feature at Godaddy’s or even in Thunderbird, though not likely in a .x release.

You might be able to find out more by e.g. making Thunderbird copy messages to some other folder, or by starring a message on one end and observing the sync delay you mentioned. I also agree this is no big issue and understand you would rather don’t reinstall Thunderbird. Of course you could consider setting up this account only on another system for a test, even using an older or nightly Thunderbird version if you like.

Please note that your input would be very welcome in order to find a bug, if any, but you are free to decide for yourself. Since the bug mentioned above is still open, I suggest you submit the issue there in case it is related. If acknowledged as an issue, you may be asked to file a new bug.

Problem Solved!

It is a GoDaddy email configuration problem. It must have been created by a GoDaddy software change or update. Here is the issue and the solution.

In GoDaddy Webmail there is the ability to set up a "preferred Sender" which means that messages from a specific sender can be highlighted in some way. I believe that in some recent GoDaddy update it must have automatically added the owner's email address (mine) to the "preferred Sender" list and then always added the star as a highlight.

To repair the problem I simply when to Settings>Preferred Sender and then deleted my user name from the list. Problem solved!

Thank you for all of your help.

Glad to be of help. Well well, some implementation after all. :)

I just found this page at Godaddy and submitted feedback about mentioning stars. Hope it will be added.