In the recent iExplorer PC update, we switched to using Windows Media Player for the audio and video previews, and voicemail files are in the AMR format which require a separate codec to play in Window Media Player. We had been using QuickTime for those previews but decided to switch after Apple’s announcement several months ago about QuickTime being vulnerable to hacking and since Apple stopped updating it.
We will look into ways to still be able to preview voicemail AMR audio files in the iExplorer window and should have an update released for it soon. For now, you will need to export the file to your computer and play it from there, and you may consider converting it to a more common file format such as MP3 or M4A. Our voicemail export article covers this and explains how to do it with our free file convertor app Adapter.
How to transfer iPhone voicemails to computer