What Is an XTM File?
A file with the XTM file extension is most likely a CmapTools exported map. These files use the XML format to store graphics and text for use in the IHMC CmapTools (concept map tools) software. The Xtremsplit software uses XTM files, too, but they are unrelated to maps. Instead, they are used to split a large file into smaller pieces, and also to join said pieces back together, so that they’re easier to send online.
How to Open an XTM File
If your XTM file is a map, it can be opened on Windows, macOS, and Linux with the IHMC CmapTools software. This software is used to express concepts in a graphical flowchart form. Since XTM files are based on the XML file format, any program that opens XML files can also open XTM files. However, the purpose of the CmapTools software is to create a visual representation of the text, annotations, graphics, etc., that’s easy to read and follow in sequence, so viewing the data in an XML or text file viewer like a text editor, isn’t nearly as beneficial as using CmapTools. Xtremsplit data files are named something like file.001.xtm, file.002.xtm, and so on, to designate the different pieces of the archive. You can open them with Xtremsplit. It’s possible that a file zip/unzip like 7-Zip, or the free PeaZip can be used to join these XTM files as well.
How to Convert an XTM File
In CmapTools, go to File > Export Cmap As to convert from XTM to an image (like BMP, PNG, or JPG) or to PDF, PS, EPS, SVG, IVML, HTML, or CXL. A file that has been split into XTM files definitely can’t be converted to any other format until it has been rejoined using Xtremsplit. For example, an 800 MB MP4 video file is unable to be converted to any other video format until the pieces of it are joined back together into the original MP4 format. As for converting the XTM files themselves, you simply can’t do it. Remember, these are pieces of a larger whole that need to be joined for any practical use. The individual XTM files that make up a file (like the MP4) are of no use apart from the other pieces.
Still Can’t Open the File?
If none of the above suggestions work to open your file, there’s a good chance you’re not really dealing with an XTM file. Some files use a file extension that looks an awful lot like XTM even though the formats have nothing to do with each other. For example, XMI files share two of the same letters as the XTM file extension, but they could be Extended MIDI files that have nothing to do with the other formats mentioned on this page. TMX is similar. That file extension belongs to the Translation Memory Exchange file format and requires a different program to open the file. Of course, none of these formats are related to Microsoft Excel files either, like those that end with the XLTX, XLSX, and XLL file extensions.