2013 file extension - Any data file created in 2013
What is 2013 file? How to open 2013 files?
The 2013 file extension is maybe associated with various file formats and programs.
The *.2013 file might store some kind of backup, financial, tax preparation, business, calendar, schedule, accounting data etc.
If the file name contains two extensions, try to rename the file to the original extension (delete the 2013 extension from the file name).