Sometimes When we download the update in Windows Server 2016/2019 via a proxy server, at times, the download process get stuck at "Downloading Updates 0%". This Windows issue generally happens when the system cannot find software update.

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to perform related Windows queries.

In this context, we shall look into how to resolve this Windows error.

Main Cause of Windows Update Stuck At "Downloading 0%" On Server 2016 ?

When there is a complicated setup with the different version of servers, multiple Internet gateways, and proxy servers, then you will face random issues with Windows updates. At times, the update process may get stuck with the following message:

Downloading updates 0%

It will detect the available updates, but when it started downloading, it is stuck at 0%. The Windows Update client has been able to send/download the updates metadata (the list of necessary updates has been formed successfully), but none of them could be downloaded.

Some of the common reasons for Windows Update Stuck At "Downloading 0%" include:

• The firewall is not active.
• Web proxy setup.
• Corrupted catelog folder.

How to resolve Windows Update Stuck At "Downloading 0%" On Server 2016 ?

1. Check the Windows Firewall Service/status

• In Windows 2016, the firewall should be on and active to make Windows update work. 
• If we disable the Windows Firewall completely, the update will get stuck at 0% without any progress.
• Visit the Services under server manager, make sure that the Windows firewall service is running. If it is not, start the service.
• Confirm whether the Windows update works now.

2. Check the Internet Proxy Settings

In most cases, Windows update cannot download the packages via the web proxy (though it depends on the authentication and security policy of the web proxy).

Check and confirm that there is no proxy setup on the web browser.

Therefore, we should remove the proxy settings and have direct internet on the Windows 2016 server to get working Windows updates.

The proxy server settings for the Internet Explorer in Windows Server 2016 do not work in the same way as in previous Windows versions. 

If the Windows Update client can access the Internet through a proxy, we must force set the system proxy for winhttp.

We can see the current proxy status in the command prompt with the below input:

netsh winhttp show proxy 

Here, in most cases, it does not set the proxy settings for WinHTTP. The proxy configured in Internet Explorer was on the User level but not in System level (WinHTTP). This configuration causes the connections to Windows Update to fail.

We can set the system proxy parameters for WinHTTP as follows:

netsh winhttp set proxy proxy-server="XXX.XX.XXX.XX:3128" bypass-list="*.ibmimedia.com"

Alternatively, we could also do this, by importing the settings from IE :

netsh winhttp import proxy source=ie

After changing the proxy settings, restart the Windows Update service:

Restart-service wuauserv

After specifying a proxy for WinHTTP, Windows Server 2016 starts to download updates from Microsoft Update servers.

Also, we will not be able to get updates through a proxy server that requires authentication, since the Windows Update client does not support proxy authentication (unlike PowerShell). In order for the Windows Update to work correctly, we must allow anonymous access to Microsoft Update servers on the proxy servers. 

The list of URLs include:

*.microsoft.com
microsoft.com
*.windowsupdate.com
windowsupdate.com
*.trafficmanager.net
trafficmanager.net

3. Clean the Update Catalog Folder

Corrupted Windows update content folder/file/catalog stops the update from further. Cleaning up the folder may help to resume Windows updates successfully.

Before doing the cleanup, we need to stop the service.

For this,

i. Go to the Services and locate the Windows update service. Stop the service.

ii. After the service stops, go to the following folder location and delete all content (files and folders):

C:\Windows\SoftwareDistribution

This is the place where OS downloads the updates. Cleaning up these files/folders and starting the service will help.

iii. After deleting the files, start the same Windows Update service we stopped initially. This will restart the update service and download the updates which stuck at 0% on Windows 2016 server earlier.

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