Why won't my update install?

Updates fail for undramatic reasons: not enough space, a dropped connection, or a partially downloaded file that the system keeps retrying. None are serious, but leaving a device unpatched is, so it is worth resolving rather than dismissing.

Safety

Step by step

1. Check free storage.An update needs far more space than its download size — often three or four times, for unpacking and rollback. This is the most common cause of failure.
2. Restart and try again.Clears stuck processes and locked files. It solves a surprising proportion on its own.
3. Check the connection is stable.Use wired or a strong wifi signal. A download interrupted repeatedly produces a corrupted file that keeps failing to install.
4. Delete the partial download and retry.Both systems have a way to clear the update cache. A corrupted partial file will fail forever until it is removed.
5. Plug it in.Most devices refuse to install a major update below a certain battery level, sometimes without saying so clearly.
6. Run the built-in troubleshooter.Windows has an update troubleshooter that resets the relevant services automatically. Worth a try before anything manual.
7. Wait longer than you think.Major updates can sit at a percentage for an hour. Turning off during installation is far more damaging than waiting.
8. Check the device is still supported.If the model has reached end of support, the update will never install. That is a replacement decision, not a fault.

Tips

• Back up before a major system update. It rarely goes wrong, and when it does you will be very glad of it.
• Install updates when you have time, not when you need the device. A major update can take an hour.
• If a specific update fails repeatedly, search its identifier — known problems and fixes are usually documented.

Questions people ask