OK, so I am having this problem as well in the past couple of days only. Adding movies I have never watched before but they appear as if I have watched the first few minutes and No have never watched a preview for it. Same with new tv shows
Here is the XML info
HELP67044.zip (1.2 KB)
Here is log files Plex Media Server Logs_2018-12-14_17-26-00.zip (2.9 MB)
I am pretty sure this is a totally different issue from the above.
I’d disable the DLNA server in Plex,
Restart the Plex server
Add some new media
Wait a few days.
If it doesn’t happen to those new items anymore, you can be sure that it was caused by a DLNA compatible device or a software in your house.
Some of these are building a media library of their own. For this they play the videos for a short time, to create a screenshot.
Either find the responsible device and disable its “library creation” activity
Or
Disable “timeline reporting” in the DLNA preferences of Plex (which causes playback activity by DLNA devices to get ignored)
Or
Disable DLNA totally
Thanks Otto. Spot on!!! turned off DLNA and problem solved. THANKS SO MUCH!!!
I can verify that this is due to watching a trailer of the movie. This only happens when you are viewing the trailer using the cinema trailers before a movie. If you already have the movie in your library and enter the movie directly and play the trailer it will not exhibit the watched behavior. However if the cinema trailer before movie happens to play it, regardless if it is in your library or not it will mark it as played.
Examples:
Movie A (Exist in library unplayed)
Movie B (Exist in library unplayed)
Movie X (Does not exist in library)
You select Movie A to watch. Trailer for Movie B and Movie X play before your main viewing of Movie A. All movies A, B, and X will mark as played. You wont notice on X as it doesn’t exist yet. It will be added to library as normal but already have a played status.
Fix this please.
i post this last year in Sept and still not fixed, sad 
Yep i have been thinking of dumping Plex for a while now. It is very buggy and presents issues all the time. Shame on me for giving them money for the garbage they put out now. Yep hope you read this Plex… Maybe you could bring it around?
I can confirm that I am having the same issue as well. Running PMS on a QNAP NAS. Any status update on getting this fixed?
i noticed that there is a new PMS update, is the problem fixed regarding this post ? because i am waiting since when i open the post to see a fix
Turning off DNLA fixed the problem for me
I unticked “Enable the DLNA server” and it worked for me.
for me disabling any DLNA has no effect, i am on the same situation, this is a bug that has to be fixed, is like this for months now
how come that this problem is not solved in 7 f*****g months of posting, every now and then i see PMS updates with same unfixed bug which make trailers obsolete, how long i have to wait for a fix to be implemented ?
From what i see plex team is ignorant and rude
I noticed this a couple of month ago and now i see that this bug is old and this is unbelievable that it is not fixed.
i can confirm, that if i watch trailer (cinema trailer before movie) then the movie that trailer was about is marked as watched. Just today i added new movie i have never seen before and it got marked as watched when added. That happened today.
This is unbelievable that such a bug is left unfixed for such a long time.
oh, i just noticed that this thread is for windows server. i’m using linux server.
i migrated to Unraid same thing, i think is from PMS on all platforms , at the moment i feel i do not take advantage of my plex pass, that how 50% of the time i added my movies in my library
I just noticed this today after 3 new movies added to my library all in watched status. They are all recent cinematic releases which I’ve seen trailers for. Pretty unbelievable that not only has this not been fixed in the 7 months since it was first raised in this thread but also no one from Plex has even responded to this thread to comment on whether they are working on a resolution or not.
Also running Plex on unRAID.
The only solution i found was to disable the trailers before movies. I just watch trailers on you tube now. Emby is looking better each and everyday Plex F’s us Plex Pass users in the A.
what someone has to do here to receive a replay from plex team ? since all of us paid for Plex Pass , what is this childish ignorance ? if that is the case i want re refund since i do not benefit of the feature " Include Cinema Trailers from new and upcoming movies in theaters"…
I have the same issue and verified the behavior described by ndoty.
Fix this please
