How to open Apple iPhone ringtone format .m4r files
Have you had trouble opening the m4r file on your computer? What are m4r files? We explain what they are and recommend software that we know will open them.
What is m4r file?
An m4r file extension is used for ringtones that is used by Apple iPhone. iPhone ringtones are stored in the same m4a audio format as songs. However m4r file extension is used to differentiate ringtones and songs.
Apple iPhone ringtone format description
The m4r file extension is associated mainly with the Apple iPhone.
The m4r file contains ringtone in M4A MPEG-4 audio file format, which is used as the default audio format to store songs in iPhone. Basically M4R file extension is used only to differentiate ring tones from songs in iPhone, but otherwise it is exactly the same format.
iTunes are used to transfer ringtones to iPhone. Select a m4a file, that you want as your ringtone, rename file extension M4A to M4R and double click on it.
iTunes will import the m4r file to its database and will put it in Ringtones library as well. After that connect iPhone to computer and in iTunes drag the ringtone and drop it on your device.
In iOS version 5, Apple introduced new Tone Store, where users can buy ringtones for their iPhones. Ringtones are downloaded to phone immediately after payment is processed.
The maximum length of m4r ringtone must be max. 40 seconds.
Suggested software to open m4r file

Apple iTunes for Windows
Multimedia file manager and library for Apple users

Apple iTunes for Mac
Program used to organize and plays your digital music and video

Apple iOS
Operating system for Apple iPhone, iPad and iPod Touch devices