Insider Preview builds on Windows 10 has a built-in "time bomb". Each comes with an expiration date, and Windows will eventually refuse to start after that date. Here's how to check when it's going to happen.
What happens when a Windows 10 building expires?
This applies only to unstable Insider Preview versions of Windows 10. Stable versions of Windows 10 will never "expire" and stop working, even when Microsoft stops updating them with security patches.
When a Windows 10 building expires, Microsoft says that you will be notified that you are using an expired building. The alert will appear again once a day, and you will also see alerts for UAC (User Access Control). Earlier reports have said that Windows 10 restarts every three hours after it expires, so Microsoft may have made the finishing process less annoying.
Earlier, Microsoft said that expired buildings no longer start two weeks after expiry date. You must reinstall a newer Windows building or an older stable building that does not expire – to use your computer again.
Microsoft expires these buildings to prevent people from staying with old, unstable versions of Windows 10. These Windows 10 buildings are available for testing, and there is no need to test an old building that has a lot of already fixed bugs.
How to check the expiration date
You can check the expiration date from the Winver application. To open it, press the Windows key, type "winver" in the Start menu and press Enter. You can also press Windows + R to open the Run dialog box, type "winver" into it and press Enter.
This dialog shows how exact the expiration date and time of your Windows 10 building are. You should update to a newer Insider building of Windows 10 (or return to a previous stable building) before expiry date.
The Winver dialog also shows the exact Windows 10 building you are using. This information is also available in the setup app.
RELATED: Are you using Windows 10 Insider Preview?