Software & Apps File Types What Is an MOS File? How to Open, Edit, & Convert MOS Files By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated October 09, 2019 File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More Tweet Share Email A file with the MOS file extension is a Leaf Raw Image file produced by cameras such as the Leaf Aptus series. MOS files are uncompressed, so they're typically a bit larger than most image files. MOS also stands for some technology terms that have nothing to do with a file format, such as Microsoft Office Specialist, My Oracle Support, Mobile Office System, Mobile Operating System, and Maintenance Out of Service. How to Open an MOS File The default photo viewer in Windows is one free MOS viewer. RawTherapee is another free software program that opens MOS files in Windows, Linux, and macOS. MOS files can also be opened with paid programs like Adobe Photoshop, Corel PaintShop Pro, and Phase One Capture One. Another option is File Viewer Plus, but the free version doesn't support MOS files, so you have to pay to use it with Leaf Raw Image files. It also only works with Windows 10. Mac users can view an MOS file with ColorStrokes, in addition to Photoshop and Capture One. If you find that an application on your PC does try to open the MOS file but it's the wrong application or if you would rather have another installed program open MOS files, learn how to change the default program for a specific file extension in Windows. How to Convert an MOS File Most, if not all, of the programs above that can open MOS files can most likely convert them, too. Just open the MOS file in one of those programs and then look for a File > Save As, Convert, or Export menu option. If you try converting the MOS that way, you can most likely save it to formats like JPG and PNG. Another option would be to use a free image file converter like CoolUtils or CloudConvert, which are online MOS to JPG converters (the conversion works through your browser). Some other options on those sites include saving MOS to BMP, TIFF, GIF, ICO, PNG, and PDF. If you need to convert MOS to DNG, you can do so with Adobe DNG Converter. Still Can't Open the File? Be careful to not confuse another file format for an MOS file. Some files use similar looking file extensions even though the formats are unrelated. MODD and MOV files are just two examples. If you really have a MODD or MOV file, follow those links to learn more about the formats and which programs can open and convert them. The software that works with a MODD or MOV file isn't the same as the programs necessary for using MOS files, and vice versa. MSO is another really similar file extension that's most likely either a Microsoft Office Macro Reference file or an Inline Email Attachment file, both of which are likely used with a Microsoft Office program.