Opening U21 files
Did your computer fail to open an U21 file? We explain what U21 files are and recommend software that we know can open or convert your U21 files.
What is an U21 file?
While we do not yet have a description of the U21 file format and what it is normally used for, we do know which programs are known to open these files. See the list of programs recommended by our users below.
We are constantly working on adding more file type descriptions to the site - the current count exceeds thousand by far, and more information about U21 files will hopefully be added soon.