By 'Windows Network' I mean the 'network' next to 'this PC' in file explorer. Assume a video exists at "\\DEVICE\Shared\sample.mp4". Then set 'source: "file://DEVICE/Shared/sample.mp4"' makes QML MediaPlayer load the video back in 5.15. But it is not doable in 6.4/6.5 anymore.

2 reproducers attached. Changing the source of MediaPlayer (29/30th line of main.qml for Qt651 and Qt51513 project respectively) to a video on another device available via network. Qt51513 (running with 5.15.14 produces the issue too) plays the video normally but Qt651 does nothing.

Another observation is about our QML Mediaplayer example. Either file is opened via 'Open->choose from dialog' or 'URL -> give a url', a video from network results in an error 'failed to load source'. The example does not exist for 5.15 so I don't know how it works. But probably should work. So I highly suspect if it is a regression.