Trialware is one type of shareware.ref>https://www.yourdictionary.com/trialware</ref> It is software that the user can only use for a short time. Then it expires. If the person wishes to keep using the program, he or she must buy a registration key or password. Trialware may be set up by date or days. For example, a 30-day trialware program may expire in 30 days or after it has been used for 30 non-contiguous days. Also called "demoware," sophisticated trialware prevents a user from installing new trial versions over and over without paying. For example, it can look for a hidden file or an entry in the Windows Registry that it created when it was previously installed. See shareware and wares.