Why did I get error 0x80042521?

Windows Update continous fails to search for Updates or cannot install them. The source of this problem could be various things as
> Windows Registry
> Windows Filesystem
> Internet access

> Windows Update service
> File corruption
> Misconfiguration
> Adware
> Virus and Malware

How to fix Windows Update error 0x80042521?

However, if you’re technically savvy, you can try the steps below:

1. Click Start and start typing on your keyboard for "services.msc"

2. In your search results "services.msc" should show up. Open it with a click.
3. A new windows will open containing all Windows services on your system.

4. Search for "Windows Update"
5. Right-click the "Windows Update" and then click Stop.

We will now clean the Windows Update temporary cache folder:
1. Hold your windows-key pressed and hit "R" key simultanous.
2. A small new windows will appear.
3. Type %windir%\SoftwareDistribution\DataStore in this new window and click OK.
4. This will open Windows Explorer on the correct location.
5. Delete all contents of this folder. (Hint: Use Ctrl + A to select all files and folders)

Now we will start the Windows Update Service again:
1. Switch back to the windows Services.
2. Locate Windows Update.
3. Right-click on it and choose Start.


If the problem still persists, you can run the System File Checker (SFC) utility. This handy in-built tool will check your filesystem.
1. Click Start and start typing on your keyboard for "cmd".
2. In your search results cmd should show up with an black icon.
3. Right-click it and select Run as administrator.
4. If you are prompted for the admin password, enter the password and click OK.
5. A new completely black windwos will open. You can type commands directly into this window.
6. Type sfc/scannow and press Enter.
7. This process will take a long time. You can minimize this black windows and work on.
Come back to the black window after a time and check if the process finished.
As soon as the SFC process finished, restart your computer. After the restart you search for Updates again.


You are still facing the same issue?

1. Restart your computer.

Next thing is to clean Windows Update download path. These steps are only for expirienced user! If you mess up your computer with Regedit, you could loose your files! Take care or use a professional tool to investiagte your computer.
1. Hold your windows-key pressed and hit "R" key simultanous.
2. A small new windows will appear.
3. Type regedit in this new windows and hit Enter.
4. In the new windows you have a navigation on the left side. Use it to navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
5. Once you found it, search for WUServer and WIStatusServer in the right hand pane.
6. If they are not listet we cannot clean the download path. Othwerwise delete both.
7. Restart your computer.

Try to search for new Updates again.
You are still facing this issue? I think this is not an usual problem and your computer should be checked by professional.
Try to look for a solution here or search further in the search box below.



Advanced information

The following Windows verisons are affected by this error:
> Windows Vista
> Windows 7
> Windows 8
> Windows 8.1
> Windows 10
> Windows 10 Redstone 2
> Windows 10 Creators Update
> Windows Server 2008 R2
> Windows Server 2012
> Windows Server 2016
volume count VDSEINVALIDPLEXCOUNT zero must plex vdserrh than greater 0x80042522 0x80042523 VDSEINVALIDPLEXORDER VDSEINVALIDMEMBERCOUNT member nonzero MSVDS indexes pack Virtual Protocol Error Disk Service increase start MagNumDB 0x8004362F IMAPIEMEDIUMNOTPRESENT Number Magical Intellectual Property CLASSENOAGGREGATION FTEENOTPROCESSEDDUETOPREVIOUSERRORS 0x80040110 Sleuthing HRESULTS Kits10Include100162990umvdserrh13670 Software User 9505 9506 0x004 27092011 ProgramFilesx86Windows 7678102 UInt32 Database Kits10Include100162990umvdserrh13580 2147755297 define HRESULT0x80042521L 2147211999 SystemUInt32 0x8004020F same from disks 0x80042520 allowed operation VDSEPACKONLINE support does system shrinking Specified VDSEMULTIPLEPACKS 0x8004251F online HRESULTinfo DVEDVTARGETDEVICESIZE 0x8004006C 0x80040003 VDSEVOLUMEGUIDPATHNAMENOTALLOWED 0x8004290D OLEEADVISENOTSUPPORTED Codes offline packs MSDN 14072016 file Microsoft