Many ready-made virtual machines (VMs) which run on VMware Player, Workstation, and other virtualization software are available for specific purposes, either for purchase or free of charge. For example, a free Linux-based “browser appliance” with the Firefox browser installed is available that can be used for safe Web browsing; if infected or damaged, it can be discarded and replaced by a clean copy. VMs can be configured to reset after each use without the need to recreate from the original file. Suppliers of operating systems with commercial licences usually require installations to be licensed; VMs with such operating systems installed cannot be distributed without restriction. Ready-to-use VMs with Microsoft or Apple operating systems installed, in particular, are not distributed, except for evaluation versions.