If you receive Windows Update error 80070490, it means that a file (CBS Manifest) that's needed to install updates is corrupt. To correct this problem, you'll need to repair Windows. Repairing Windows won't damage your personal files or the programs that are installed on your computer.
The System Update Readiness Tool for Windows can correct some conditions that cause Windows Update error 80070490. You can access and run this tool by reading this Knowledge Base article on the Microsoft website.
If the System Update Readiness Tool doesn't correct the problem, you'll need to repair Windows. Repairing Windows won't damage your personal files or the programs that are installed on your computer.
Once you finish the repair, you'll need to rerun Windows Update to install any updates aren't included on the installation DVD. To repair Windows, follow these steps:
Close all programs, and then restart your computer.
Insert the Windows DVD into your computer's disk drive. Wait for Setup to start. If Setup doesn't start automatically, follow these steps:
Click Start, and then type Drive:\setup.exe in the search box. Replace Drive with the letter of your computer's DVD drive (for example, D:\setup.exe).
In the Programs list, click Setup.exe.
Click Install Now.
Click Go online to obtain the latest updates for installation (recommended).
If you are asked for it, type the Windows Product key.
In the Which kind of installation do you want? window, click Upgrade.
When the installation is complete, restart your computer, and then run Windows Update.
If you continue to see this error, see this automatic troubleshooter
on the Microsoft Support website, or go to the Microsoft Answers
website for more assistance.
Error codes this applies to: