I would like to ask you if C:\ProgramData\SOFiSTiK\cache\p folder (17GB in my case) is useful, or if it contains installation files only and it could be deleted.
In this folder we save the installation files. You may delete this folder.
As soon as you perform an update with the SOFiSTiK Application Manager (SAM) the folder C:\ProgramData\SOFiSTiK\cache\p will be created again.
Have a nice day