2011 file extension - Any data file created in 2011
What is 2011 file? How to open 2011 files?
The 2011 file extension is maybe associated with various data file types. File could be created or backed up in 2011.
Also may include some kind of financial, tax preparation, business, calendar, schedule, accounting data.
If the file name contains two extensions, try to rename the file to the original extension (delete the 2011 extension from the file name).