Check your anti-virus software program if you encounter a virus warning while launching Silhouette Studio. 

NOTE: So long as Silhouette Studio was downloaded directly from the official Silhouette website, we can confirm that the Silhouette Studio installation program and subsequent Silhouette Studio files are free of any viruses, Trojans, malware, adware, or other harmful components.

As all antivirus applications are different, you will need to check your antivirus program's website for instructions on how to add Silhouette Studio as a trusted application.