Each institution (and each LMS) presents a different set of criteria as to file types, embedding, etc.  Because of this, each institution must use trial/error in determining what methods to use in regards to working with media files. This would also include PDFs and spreadsheets. 

Troubleshooting these methods on behalf of institutions typically falls outside the scope of Respondus Support.

You should try hosting the files in the course file space, then in the quiz question provide a link to that file. If the file does not open in LockDown Browser, you should then try linking to an externally hosted file (outside of your LMS server). 

Another key to whether the file opens is whether all the necessary permissions are set correctly. This would include:

* on the operating system level.
* on the server where the file is hosted.
* the file itself.
* the LMS.

Whether or not a file plays/opens correctly on a Mac or Windows computer also depends on several other factors, including:

* is the file being used corrupt?
* is the file copyrighted? If so, there may be DRM (Digital Rights Management) issues not allowing it to play on all operating systems. MAC may have different DRM qualifications than Windows.

An excellent way to test the file is to remove the LDB requirement from the exam, then take the exam using various non-locked browsers (Google Chrome, Safari and Firefox). This troubleshooting method can often reveal problems with the file.

In general, regardless of LMS and OS, we recommend "MPEG-4" (".mp4") for videos and "MP3" (".mp3") for audio. Both of these formats are somewhat de facto formats that will play on variety of systems (Windows, Macs, Linux) including mobile devices (iOS, Android, Windows).

Various other video and audio formats such as QuickTime .mov, and Windows ".wmv" along with the uncompressed formats of ".AVI" videos and ".WAV" audio are not recommended.

When using Respondus 4.0 and its media wizard to publish the question and media content, the media files get placed in the LMS's content area. However, this process doesn't guarantee that LockDown Browser will be able to access those files, as so much of that is out of our control. If problems are encountered, our recommendation is to link to an externally hosted file.