Error 0x80240034 with Windows 10 is caused by Windows Update cannot download the various files it requires to perform updates that Windows requires.

The error is specifically referred to as the “WU_E_DOWNLOAD_FAILED” error, which basically means that the system has not downloaded the correct “Windows Update” files.

The resulting problem means that the system cannot handle the updates needed to run, leading the system to show incorrect behavior.

To fix it, it essentially needs to fix any of the major issues that prevent Windows Update from downloading the appropriate files – this is about having the ability to fix similar Windows Update service, as well as being able to repair any of the underlying software applications that integrate with Windows.

You will typically see the message for the error as follows:

Unable to install – 0x80240034

The causes of the error will typically be:
Internet connection issues
Microsoft Update Server Errors/Issues
Error with update payload itself
Other miscellaneous error with update (perhaps third-party virus/software issue)
The way to resolve the error is to make sure that the various files that Windows Update requires to function properly. This can be done by following these steps:
1. Run the Windows Update troubleshooter

The first step is to run the Windows Update troubleshooter.

This is a tool included with Windows 10 (and I think Windows 7) that allows you to clean up any of the problems that Windows may have with its underlying processes “update”.

To do this, you can follow these steps:

Press the keys “Windows” and “I” on your keyboard (load “settings””)
Click “Update & Security”
In the left pane, select “Troubleshooting”
In the list that appears, select “Windows Update”
Click “Run this troubleshooter”
Let the process run
When you’re done, restart your PC
This probably won’t resolve the error, but you need to fix most of the problems that you form with the update service.

2. Run SFC and DISM

After you perform the previous actions, you must run the SFC and DISM commands.

These are small command-line-based applications within the Windows system, designed to give users the ability to clean up most of the problems that are formed with Windows.

You can do this using the steps described here:

On your keyboard, press the “Windows” and “S”” keys.
Type “CMD”
In the first list that appears, right-click and select “Run as administrator”
In the black box that appears, type the following commands:
“SFC /scannow” – press “Enter”
“DISM /Online /Cleanup-Image /RestoreHealth” – press “Enter”
This will run a series of “scans” that will basically make sure that the system is able to run the various files/settings that it requires properly.
Although this may not solve the problem (although you should do it for 40% of cases), you should fix a large number of underlying issues that could lead to showing.

3. Manually restart the Windows Update service

Next, you must manually restart the Windows Update service.

This is a bit complicated, but it has to be the biggest contributor to a solution.

Basically, the way Windows Update works is with what’s known as a “service”.

It is an application that runs perpetually in the background of the system and allows a number of other processes to be used at will.

The Windows Update service is responsible for continuously downloading, resuming, and updating the various items required to perform updates on Windows.

Unfortunately, it is often the case that the system will end up having problems with the service, which can be fixed by manually restarting:

On your keyboard, press the “Windows” and “S”” keys.
Type “CMD” and in the first item that appears, right-click and select “Run as administrator”
In the black box that appears, type the following commands:
‘net stop wuauserv’ – ‘Enter’
‘net stop cryptSvc’ – ‘Enter’
‘net stop bits’ – ‘Enter’
‘net stop msiserver’ – ‘Enter’
‘Ren C:’Windows’SoftwareDistribution SoftwareDistribution.old’ – ‘Enter’
After you do this, you will need to start the various services again. This can be done using the following steps (back in the same CMD panel):
‘net start wuauserv’ – ‘Enter’
‘net start cryptSvc’ – ‘Enter’
‘Net Start Bits’ – ‘Enter’
‘net start msiserver’ – ‘Enter’
This should be followed by running the Windows Update command again.
4. Temporarily disable Firewall/Antivirus

Finally, one of the most common causes of the problem is a “fake flag” of the caliber of your antivirus application or firewall.

This happens because the system basically thinks that (for some reason) the Windows Update service is causing irregular (potentially malicious) Internet connectivity and therefore will block it.

To resolve this issue, you can follow these steps:

If you are using a THIRD PARTY antivirus
Right-click the security software icon at the bottom right of the Windows taskbar
Select the equivalent of “pause” (can be “Game Mode” / “Temporarily Stop” etc.)
Select “10 minutes” or the equivalent
Try running Windows Update again
If W Update isn’t working right now, try step 3 again with the antivirus temporarily disabled
Restart the system after this attempt
If you are using Windows Defender (default antivirus)
On your keyboard, press the “Windows” and “I” keys.
Select “Update & Security”
In the left menu, select “Windows Security”
Select “Virus and Threat Protection” and then select “Virus and Threat Protection Settings”
Change “Real-time protection” to “Disabled”
Try to update your system and, if it doesn’t work, try step 3 again
After this, re-enable the Windows Defender service, restart the computer
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If the above doesn’t work, you’ll probably have deeper problems with your system. Of course, a generic article on the Internet will not solve the same.