Notes about the SSO file extension:
To open this file type, a required software must be installed. Without it you only see a Windows message "The following file cannot be opened
" (Windows 7) or "How do you want to open this file?
" (Windows 10) if you double-click the file. There click on "More apps"
and choose a suitable software to view such files on your PC or from email attachments.
The SSO file type is primarily associated with 'ChessDB' by Dr. David Kirkby. ChessDB is a database program used for storing chess games. A ChessDB format database consists of three files: .SI3 (index file); .SN3 (name file); .SG3 (game file) (those 3 are needed to make one database). These are all binary files. Some complete databases are held on the ChessDB web site. At the time of writing, one database (called 'huge') has over 3.5 million games. Other files used in ChessDB are: .PGN (Portable game notation, which is used in lots of chess programs, so is not unique to ChessDB); .EPD (Extended Position Description); .SSO (Search options file); .SOR (Repertoire file); .DAT (used on four files - engines.dat history.dat options.dat and recent.dat) to hold configuration information. All are text files.
Detailed information for file extension SSO:
File classification: Database
To change file associations press Windows Key
and then Apps and Features
> Default apps
> Choose default apps by file type
Invalid file associations could be the result of underlying issues within your Windows PC.