Hi Panayiota Zagrimani,
I understand how frustrating it can be when both the Windows Insider feature update and the Microsoft Defender Security Intelligence update fail to install.
To help narrow this down, could you please share the following details?
- Your current Windows version and OS build. Press Windows + R, type
winver, and share the information shown.
- The Insider Channel listed under Settings > Windows Update > Windows Insider Program.
- The amount of free space available on drive C: under File Explorer > This PC.
- Whether the device is personally owned or managed by a workplace or school.
In the meantime, please try these steps:
- Go to Settings > System > Troubleshoot > Other troubleshooters, then select Run next to Windows Update.
- Restart the computer after the troubleshooter finishes.
- Open Windows Security > Virus & threat protection > Protection updates, then select Check for updates.
- Once the Defender update installs successfully, return to Settings > Windows Update and select Check for updates again.
Please also confirm that the device has a stable Internet connection and sufficient free storage before retrying. Microsoft provides additional Windows Update troubleshooting guidance here: Troubleshoot problems updating Windows.
If the errors continue, please let me know which step fails and share any new error code shown in Windows Update > Update history. Please hide any email address, device ID, product key, or other personal information before posting a screenshot. I look forward to your update. Thank you so much for your understanding.
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