Notes about the EFW 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 EFW file type is primarily associated with 'CA Security Center' by CA. Use an editor to look at the first two characters in the file. If they are PK then the file is a renamed ZIP file; if MZ then the file is a renamed EXE file; if Rar! then the file is a renamed RAR file. Rename the file accordingly and then either use an archive utility like 7-Zip to open the file or run it as a program. Be VERY careful with these files as an anti-virus program has renamed them for some reason. They could be infected.