If you are using a screensaver from untrusted sources, it can also cause the screensaver issue. Well, you may experience such an issue because of some change in screensaver settings, a recent Windows update, increased/decreased sleep time of the monitor, or simply because of a damaged mouse. Sometimes, people complain about Windows 10 screensaver not working as expected. Along with protecting your screen, screensavers can also add a fun element to your screen when idle.
Some windows users keep a plain black screensaver, while others like to use some animation as their screensaver. Screensaver protects your monitor from getting burnt when in the idle state.