When you have two or more operating systems installed in your computer, then all the operating systems show up at the Startup. The options display for certain period of time which is by default 30 seconds. The 30 seconds is quite a reasonable value and you get ample time to select the operating system you want to open. If you want to shorten the time span or increase it, you can. The following tutorial will help you to change time of displaying the list of OS at Startup in Windows 10.
Steps to Change Time to Display List of Operating Systems at Startup in Windows 10
1. Right click on Start Menu and go to Control Panel.
2. Now go to System and Security. Click on System. Now click on Advanced System Settings.
3. Go to Advanced tab. Tap on Settings under Startup and Recovery.
4. Under Default Operating System, find out the time to display the list of operating systems at startup. The default value is 30 secs. You can change it to your desired value.