QuickTime 5 issues: "out of date" error; Plug-in and Mac OS X

Late yesterday, we reported the release of QuickTime 5 Public Preview (as well as new versions of Streaming Servers). Note: We had a folder for QuickTime 4 called "QuickTime Folder" located at the root level of our drive. QuickTime 5 software was not installed there; instead we found it in the Applications folder, in a folder called QuickTime. Solving the "out of date" startup error Many MacFixIt readers are reporting a problem with the Preview: After installing the software and restarting, you will get an error that says: "Some of your QuickTime components failed to load because they are out of date." If you accept the option to try to update the software again, it will likely do nothing and the error will appear again the next time you restart. The solution appears to be to remove all QuickTime extensions from the Extensions folder and then select to reinstall QuickTime 5. Selecting Custom Install from the QuickTime 5 Installer, selecting the Uninstall option, and then later reinstalling QuickTime 5 should also work. However, Bev Blackwood found that if she simply ran the QT5 installer a second time, it updated 4-5 further components, after which it seemed to run fine. Update: Matthew Parsons adds: "The specific item seems to be QuickTime QD3D located in the QuickTime Extensions folder. It's still ver 4.1.1 - removing it clears the error message. My guess is either that component won't be included/supported in QT5, or it's just not done yet." Another reader confirmed this. Update: A clarification: QuickTime QD3D does get updated - to version 5.0a5c2 to be exact. The problem appears to be that selecting Full as the Installation type does not install as much as selecting Custom and then checking everything. Doing the latter should install the QD3D update the first time around - and avoid getting the error message. QuickTime 5 plug-in and Mac OS X QuickTime 5 Preview is designed to run in Mac OS 9. However, installing it may cause some glitches for those who also have Mac OS X installed (especially if it is on the same partition as Mac OS 9): Chris Comeau writes: "I installed the QuickTime 5 Preview while running Mac OS 9, and it worked no problem. However, after rebooting in Mac OS X, an "Error loading QuickTime Plugin" message appeared in the Mac OS X version of Internet Explorer when accessing a page that had an embedded movie." Steven Massey had the same problem. Chris adds: "I seemed to have fixed this by trashing the files QuickTime Plugin and QuicktimePlugin.class from the /Contents/MacOS/Plug-ins folder" (accessed by selecting to Show Package Contents for the Explorer package/application). [Note: Internet Plug-ins folders are also in the System/Library and Library folders. We are still trying to sort all of this out.]