OPTIONS | DISK menu. Clear Unused Cache Files. It's a good idea to do this prior to beginning a new project.
Location of the cache folder can also be specified there. It can be pointed to an external drive that has more free space.
Use the latest version. For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest. Retain your old install file and registration info.