Several users have reported an issue in which QuickTime cannot display web-based media content. When embedded media is accessed, the QuickTime plugin will display an error symbol.
Apple Discussions poster swairah writes:
"I have a problem with my Quick time player which is i cant see any trailers in apple site and i also cant download any mp3 whenever i try to download or watch a trailer the page turn black and there is a Question mark on the Quick time player logo."
For some users, this problem results in the question-mark symbol, but for others the QuickTime plugin gives an error message stating the users should download and install the latest version of quicktime, even though they are fully updated with the software. Users have tried addressing this problem by reapplying the quicktime update, but this has not fixed the issue.
There are a couple of procedures users can try, but this problem remains largely unresolved.
Remove "QuickTime Plugin.webplugin" component QuickTime installs two plugins into the /Macintosh HD/Library/Internet Plug-Ins/ folder: The "plugin" and the "webplugin". While both of these items should work fine together, some users have found that removing the "webplugin" file has fixed playback issues in QuickTime. Alternatively, users might try reinstalling quicktime after removing one or both of these plugins, just in case one became corrupted.
Remove unneeded components and plugins For web browsers, users should try disabling or removing all internet plugins from the /Macintosh HD/Library/Internet Plug-Ins/ folder except for the QuickTime plugins. Additionally, in the /Macintosh HD/Library/QuickTime/ folder, remove all third-party components (if unsure which are third-party, just remove them all temporarily). Then restart the computer and try loading the media in the browser again. If all is well, add components and internet plugins back in small groups, restarting between each group to troubleshoot them.
Clear Safari Cache, or even reset Safari For Safari, users might try resetting the temporary internet data such as cache files and cookies. The Cache is usually the main culprit of pages not working well, and while a few reloads of the page should reset the cache for that page, users can ensure the page is loaded fresh by going to the "Safari" menu and choosing "Empty Cache". Additionally, users might try completely resetting Safari by using the "Reset Safari" option in the same menu.