After upgrading my Centos6 based fileserver from samba3 to samba4 (through official repos), I get a strange issue:

When I browse (from windows computers) a directory with video files (with permission 777), some files (movie files .MP4, not .MKV) gets modified just by highlighing, and gets their timestamp updated. So If I have sorted a directory by "Date modified" and I highlight file2 the timestamp of the file immediately gets changed to the date and time I do this and the file gets moved to the top of the list.

I first thought it was a windows-problem, but it happens from whichever windows(7)-computer I use, and also - This only happen on the samba4 server, not the other samba3 server I have in the same network.

Anybody got a clue on how to attack this problem? google "samba4 file timestamp" does not give me anything..

I do think it is a windows problem, somehow windows will touch those files (during creating thunbnails or similar task) and somehow samba3 did not allow that modification. Or probably you removed some of those thumbnails and windows now trying to recreate them.

It happens both on old and new shares, and with the same files. On the old server (samba3) it does not happen when I test in old and new shares, with the same files.

Yea, I believe you are right when you write "somehow samba3 did not allow that modification". So... what setting??

I still have this problem, anybody else have the same problem or a solution?

Maybe someone have encountered (and hopefully solved) this problem now?
Still the same problem....

you may try to increase samba debug level and look at the logs to see what's happening