How to solve the error code 0x800705b4: Windows Update encountered an unknown error in Windows Server 2008 R2

There are several steps you can take to solve the error code 0x800705b4 in Windows Server 2008 R2:

1. Restart your computer: Sometimes, a simple restart can fix the issue. Restart your computer and try to update again.
2. Check your internet connection: Make sure your internet connection is stable and working properly. If you are using a wireless connection, try connecting your computer directly to the router with an Ethernet cable.
3. Disable antivirus software: Sometimes, antivirus software can interfere with Windows updates. Disable your antivirus software temporarily and try to update again.
4. Run Windows Update troubleshooter: Windows has a built-in troubleshooter that can help you fix update-related issues. Go to Control Panel > Troubleshooting > System and Security > Fix problems with Windows Update.
5. Reset Windows Update components: If the troubleshooter doesn't fix the issue, you can try resetting the Windows Update components. Open Command Prompt as an administrator and run the following commands:

       net stop wuauserv
       net stop cryptSvc
       net stop bits
       net stop msiserver
       ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
       ren C:\Windows\System32\catroot2 catroot2.old
       net start wuauserv
       net start cryptSvc
       net start bits
       net start msiserver
   

6. Install updates manually: If none of the above steps work, you can try downloading and installing the updates manually from the Microsoft Update Catalog website.