Why did I get error 0x80000166?

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 0x80000166?

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
PStateReg 0x00000000 0x800001880x00003815 0x80000149 0x800001660x0000440D 0x8000019C0x00002C19 0xC0010066 0xC0010065 UnKnoWnCheaTs 0xC0010067 0x8000016a Synergy VBYTE Forum Mailing type Sending paraEach entry stability timing PORT 0x30B40093 value 20para A400 0x00000157 0x00000145 SourceForge 28042005 A510 0x8003024a Optura 0x00000129 Lists gPhoto Freaks OSPF NSSA 26082009 Gone List Archive Have 0000 injecting both AHave appear xxxyyyzzz228 0x0045F0 ABRs 0x80000164 r9r8 andh r8r80x0 0x8000015e r8pc1150 0x80000162 r90x200COH 0x48005008 0x8000015A 0x48005C03 0xC0010064 CPUZ Report 0xC0010063 0xC0010071 LISTENER Issue AVnuOpenAvnu fr4int simple TALKER GitHub 000004000 supportsstatistics supportstest 17112014 firmwareversion businfo Renesas 01092016 fr1byte memory allignemnet problem VDWORD 0x8000016b VINT fr5intfr7intfr6intfr4int fr0dwa16 0x80000100 feEbyte supportseepromaccess Graphics Card 18112013 View Single 22112013 system 0x4000404C 0x40004040 0xC0010068 KILLING Tech Support Forums 0x80000186-0xC0010064">0x80000193 0x3C003403 Freezing Steam Users 0x80000186 Game Hacks Cheats 0x3C00444C 0x3C005040 Multiplayer