When you have installed Reason 10 and launch it for the first time, Reason automatically places the Factory Sound Bank, Orkester sound bank and Reason 10 Sounds in separate sub-folders in the following location on the hard disk (if they are not already there):
Mac: /Library/Application Support/Propellerhead Software/Soundbanks
PC: %programdata%\Propellerhead Software\Soundbanks
The factory sound banks will be located here so that Reason can be automatically updated in the future without affecting/deleting the existing factory sound banks. If Reason shouldn’t find the factory sound banks at this location, they will be automatically downloaded by Reason from the Propellerhead web site and placed there.
Note that if you have also downloaded the optional Drum Supply and Loop Supply ReFills in Reason 10, these will be automatically placed in the following location on your computer's hard drive:
Music > Propellerhead Content > Optional Refills