The FL Studio registration key should be called FLRegkey.Reg to see the .Reg extension, you must have your Windows Browser - Tools > Folder options > View > 'Hide extensions for known file types', unchecked (no tick).
Renaming .Reg to .efw is caused by some anti-virus software renaming files it knows can harbour viruses (.reg files for example) to something that does not run .efw.
Solution:
- Rename the file FLRegkey.efw to FLRegkey.Reg
- Run flregkey.reg on your pc by double clicking it or right-click and select 'Merge'.
Additional information:
The FL Studio unlocking registration file FLRegkey.Reg is a file that is equal to an executable .EXE file. These files are renamed by CA Security Centre to have a ".efw" extension. The Computer Associates (CA) antivirus software does this rename to prevent malicious files (viruses, malware) to be automatically ran on your pc.
FL Studio registration files that are saved as EFW files may be opened by changing the file extension to ".reg" and opening the file by double clicking it.
Attention:
Do not open non FL Studio files that have an .efw ending. Files from non-FL Studio sources could contain viruses or other malicious programs. The FL Studio file will always be named "FLRegkey.Reg" and is only available from your 'my account' page.
You can prevent EFW files from being created by temporarily disabling your anti virus software then sign in to your 'my account' page.
Don't forget to turn your anti virus software back on after you are done!
The FL Studio Support Team.