.TMT File

File extension tmt is sometimes used for temporary files. These files may be created by computer programs for a variety of purposes; principally when a program cannot allocate enough memory for its tasks, when the program is working on data bigger than architecture's address space, or as a primitive form of inter-process communication.

How to open:

You typically cannot open temporary files manually.

How to convert:

Temporary files are usually not meant to be converted to anything else and as such, it is not possible.