If you’re like over 80 million PC users around the world, then you’ve already installed Windows 10.
Unfortunately, many people who tried to install Windows 10 were greeted with an unfortunate error. They saw the dreaded error code 80240020.
That error code means your Windows 10 installation folder is unfinished and/or corrupted. Here’s how to fix it.

Step by Step Guide to Fixing Error 80240020

Step 1) Go to your C:\Windows\SoftwareDistribution\Download folder and delete everything in that folder. Note: if you get an error in this process, see the Can’t Complete Step One subheading at the bottom of this page.

Step 2) Run the command prompt as an administrator and type in wuauclt.exe /updatenow
Step 3) Navigate to your Control Panel > Windows Update. Windows 10 should automatically start re-downloading all of the necessary files.
If these three steps work, then Microsoft will download all of the Windows 10 files from scratch with no errors this time. If you still get that error code, then you may need to repeat these steps. Sometimes, your download may become corrupt if you restart or lose your internet connection halfway through.

Troubleshooting

On a Reddit thread featuring this problem, some users complained that the above three steps didn’t completely work for them. Fortunately, here are some troubleshooting tips that might work
-Some users claimed that setting their time forward one month (say, to the 1st of November) and then completing the above steps fixed their problem.
-Some users also ignored the Windows Update download entirely and chose to download Windows 10 from the official Microsoft website, which they were able to do without errors. If you use this method, just make sure that you choose Upgrade and not Clean Install. If you do a Clean Install, then Windows 10 will not activate because you would need a new product key. The free Windows 10 offer only works with upgrades. When you choose Upgrade, your product key will automatically carry over.

-In response to this error code, Microsoft offered the following solution, although you’re required to tamper with registry keys for this to work. You can view the solution at Microsoft Answers here.
-Microsoft would later endorse the original Reddit post as an official solution for the 80240020 error code. So just in case you were wondering how legit this solution was, it’s pretty legit!

Can’t Complete Step One?

Many users get stuck on step one because they can’t delete everything in their Download folder. If that’s the case with you, follow the steps below:
Step 1) Open the following folder: C:\Windows\SoftwareDistribution\Download
Step 2) Run the command prompt as an administrator. Type in net stop wuauserv. You should see a message telling you that Windows Update service has been stopped.
Step 3) Go back to your Download folder and you should be able to delete all of the contents within.
Step 4) Open the command prompt again and type in net start wuauserv. This will restart the Windows Update service, at which point you can return to step 2 in the original post.
The reason you were having this problem is because Windows Update was actively downloading files in the Download folder, and you can’t delete files when they’re in use.
Shoutout to /u/Losemind on Reddit for his original thread with the solution!