***As of March of 2022, it is no longer possible to online activate Studio One 3, Studio One 2, or Studio One version 1. For those versions, you must be do an offline activation. Here is a link to our Offline Activation article.
1. First Time Activation
Once installation is complete, launch Studio One. Upon running Studio One 5 for the first time, you may be prompted to accept the Studio One End User License Agreement, also known as the Studio One EULA.
Click [I Accept] to accept the agreement.
The PreSonus Login window is then displayed.
If you already have a user account, enter your My.PreSonus username and password, and press [Login] to log into your account.
If you don't have a MyPreSonus account, we ask that you go back to [1] Studio One 5 : New User Account & Product Key Registration and follow the steps to create your user account and register your product.
2. Activating Studio One
Studio One must be activated for use on your computer.
In the rare instance where you have multiple licenses of the same Studio One version registered to the same My.PreSonus account, you will need to select which license to activate.
The next window, click on the drop down and click on the little gray triangle pointing downward.
Choose "Show my existing Product Keys" to see your available Studio One keys.
If you have more than one Studio One 5 Product Key in your account, select the one you want to register with this installation on your computer.
Once selected, click the 
button.
If you have enough activations out of the 5 (Five) allowed in your account, then Studio One will Activate and you should see this screen. (This may look a little different on Mac)
If you have exceeded your maximum number of allowed activations, you may see this screen:
If you click [OK], Studio One will quit back to the desktop.
If you click [Manage Activations], a web browser will open to my.presonus.com. click here to go to the
Manage Your Studio One 5 Activations Guide.
Next Article: Installing Studio One 5 Sound Sets.
[5] Studio One 5 : Installing Additional Content [Studio One Sound Sets]