Why did I get error 0x800401CF?

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 0x800401CF?

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
define summary public CONVERT10ELAST const using GitHub page CONVERT10SLAST CONVERT10SFIRST HRESULTTYPEDEF0x800401C6 method HRESULTTYPEDEF0x800401C5 codes CONVERT10ESTGDIBTOBITMAP HRESULT pinvokenet CLIPBRDSFIRST OLESTREAM Blogs Code HRESULTTYPEDEF0x800401CF related hexadecimal CONVERT10ESTGNOSTDSTREAM 0x800401D0 error master failed 0x000401CF Exchange 0x000401C0 connector send server back Constants WinError mingww64winerrorh int0x800401CF Alexpuxmingww64 tool memory perfview Microsoftperfview performanceanalysis 262607 HRESULTTYPEDEF0x000401D0 perfviewHResultscs 0x100000000 header from bitmap files These HRESULTTYPEDEF0x800401C4 taken been OpenClipboard CLIPBRDECANTOPEN 0x800401D1 CLIPBRDECANTEMPTY OleSetClipboard CLIPBRDEFIRST OleFlushClipboard OleGetClipboard Enums avialable uncheckedint0x000401C0 uncheckedint0x800401CF convert Unable information IStorage library project software free DescriptionOLESTREAM uncheckedint0x000401CF Wine Copyright problem with Friday appears source brought there December support pages httpblogstechnetcombeldararchive20070403724736aspx shows 2010 Reply 0x800401CF168related Task Microsoft reported destination Cannot activate 2008 operation mail delivered after outgoing object could found Site ENUMSFIRST 0x000401B0 262576 2147221057 httpbitlyJK4AtT ENUMELAST 0x800401BF ENUMSLAST 2147221056 2147221041 262592 0x800401C0 0x000401BF 262591 CONVERT10EFIRST SystemCollectionsConcurrent SystemDiagnosticsContracts SystemReflection Win32Constantscs Home TechNet list SystemThreading details static class httpmsdnmicrosoftcomenuslibrarycc231196aspx SystemThreadingTasks namespace MicrosoftWin32