I cannot reproduce this in 64, 65 or 66 with the provided sample hosted locally, and https://download.blender.org/peach/bigbuckbunny_movies/BigBuckBunny_320x180.mp4 as the media file. Can you provide a complete sample that reproduces this? (including the media file you're using, as it may depend on that too)

Also, do you have a link to one of these crashes? (find them on the about:crashes page)

(In reply to Andreas Pehrson [:pehrsons] from comment #3) > Also, do you have a link to one of these crashes? (find them on the > about:crashes page) The browser does not crash, so no crashes on about:crashes page. Try this test: http://www.mit.edu/~rjc/dev/media-seek.html It is primarily the same file accept I'm now using video element rather than audio. Results are slightly different: - accept the default filename (it lives in same directory on server as the .html) - play the media by clicking the play button after one second timeout I seek to the 1 second mark of media by setting video.currentTime=1.0; - seek completes, media begins playing, then stops if audio element used, pressing the play button again does not restart when video element used, pressing play again does restart, and stops again after seek

Thanks for the update. This sounds a lot like bug 1512958. I'll dupe to that for now. If you test with the fix for that bug and can still reproduce, please reopen. To test that bug's fix, grab a build for your platform on https://treeherder.mozilla.org/#/jobs?repo=try&revision=446a19005dc615351231f595b3e8ad946e0ef246 You find the build among the build job's (the green "B"s) artifacts (Job details tab, once you click a "B"). For the Windows 2012 x64 opt build, this should work: https://queue.taskcluster.net/v1/task/BAZx5IomTTOvZ0Ushxm1IQ/runs/0/artifacts/public/build/target.zip