*this tip edited to reflect instructions for Mac and Linux systems with thanks to Tyrone and Chris and the instructions from Image Line Software*
To
unlock the demo, you need to download your Registry Key. All FL-Studio
customers can do this from here (you must be logged into your IL
account):
http://support.image-line.com/member/regcode.php
After
downloading the registry key, you need to import it with regedit.
On the Mac, go to 'Programs' and choose "Run Command..."
On Linux, go to 'Applications', 'CrossOver' and choose "Run a Windows Command"
Then, on both...
Select your FL Studio bottle
In the 'Command' prompt, type:
regedit
Then, click 'Run'
In 'Registry Editor' select the 'Registry' menu and then select 'Import Registry File'
Locate your FL Studio 10 registry key (regkey.reg) that you downloaded from your IL account and import it.
Close 'Registry Editor'.
FL Studio 10 should now run as the version you purchased.