The M75 file extension was reported to be used in one of the older versions of Apple QuickTime Player.
How to open:
Due the variability and uncertainty of this file type group, there is no general information available, about how to open this various data file format. However most files with extension from this group are usually not meant to be opened or viewed directly. If there are associated applications or programs listed below the extension description, you can always try to check their website for additional informations on their forums or other type of customer support.For general information try to look at:Identifying unknown file formats
How to convert:
Due the variability and uncertainty of this file type group, there is no general information available, about how to convert this various data file format. However most files with extension from this group are usually not in formats, which can be converted. If there are associated applications or programs listed below the extension description, you can always try to check their website for additional informations on their forums or other type of customer support.