If you are seeing this QTKit Warning, then X2Pro will not be able to extract audio from some of your files in the future.
It affects less than 1 in 60 X2Pro users, but if you do see it, it is important you understand what it means and why you may need to take urgent action.
If you are likely to have a lot of similar material you might be better off not ticking the 'Do not show this warning again' checkbox for the time being.
Please take a note of the files which caused this warning and contact us to discuss them. If we don't hear from you, we will not be able to help.
Visit our forum to find out how you can report the files and help us, and Apple, to help you out in future. Please go to: https://forum.marquisbroadcast.com/qtkit-warning.html and follow the instructions.
When X2Pro was first released, it used QTKit to extract the audio from media files. As time went on and other technologies matured, Apple advised developers to move to the AVFoundation framework. QTKit was deprecated in OS X v10.9 (see: https://developer.apple.com/documentation/qtkit).
As X2Pro moved over to using AVFoundation as its primary technology we found that some files that extracted fine with QTKit failed with AVFoundation. Therefore, we kept QTKit available in the background to use when files fail with AVFoundation. This happens silently “under the covers”.
QTKit was only available in 32-bit. Once the OS X transition to 64-bit is complete, 32-bit apps will no longer be supported. Apple have yet to announce when this will be (see: https://support.apple.com/en-gb/HT208436), although they have said that macOS High Sierra will be last macOS release to support 32-bit apps without compromises. (see: https://developer.apple.com/videos/play/wwdc2017/102). The X2Pro app and its other libraries have been 64-bit for some time but QTKit will soon become unavailable to us.
Once we are unable to use QTKit in X2Pro it will not be able to process the media files listed in the dialog.