XF 1.5 Why not always taken to the first unread post in a thread?

Stuart Wright

Well-known member
When opening threads, sometimes it opens at post #1 rather than the first unread.
What circumstances lead to this scenario?

Logging out?
I read that there is a data time limit of some sort?
I need to know this information so I can let my users know.

Steve F

Well-known member
It is most likely related to Read marking data lifetime option. Search the ACP for readMarkingDataLifetime



XenForo developer
Staff member
If a thread is already read (not bold), clicking it will take them to the first post in all cases.

If a thread is unread and we have a record where they may have read to, you will be taken to the first unread post. If we have no record (thus no proof they read it), they'll be taken to the first post (with a link to potentially take them to the first guaranteed-to-be-unread post).

Whether we know whether they've read a thread is based on the option @Steve F mentioned. If they've read a thread within that time, we'll have a record indicating that and will use that. If they've marked a forum as read within that time, then we'll similarly have a record and use that. If they've done neither, we won't know whether they've read the thread so we treat it as never seen before.

Increasing that value may have some performance overhead in some scenarios (so monitoring may be necessary) and it will maintain more data, but it will mean that the system tracks read data for a longer period of time.

Stuart Wright

Well-known member
Another user replied
Happens to me all the time using Chrome on an Android phone. Not sure it's time related - it can happen to me revisiting a busy thread after only a few minutes.
Is the only answer that he might not be logged in?