Windows 7 update error code 800700C1

This is with Windows 7 Home Premium 32 bit. When trying to update. I get that error code and it will not dl/install the updates. I never had this issue before and it just kinda popped up from no where. Any idea how to fix this?

Question Info

Last updated September 14, 2018 Views 10,896 Applies to:

OPTION A: For home users, visit the Microsoft Virus Solution and Security Center for resources and tools to keep your PC safe and healthy.  If you are having issues with installing the update itself, visit Support for Microsoft Update for resources and tools to keep your PC updated with the latest updates. 

Customers who experience issues installing Microsoft security updates also can visit the following page for assistance:

For more information about how to contact your local Microsoft subsidiary for security update support issues, visit the International Support Web site:

For enterprise customers, support for security updates is available through your usual support contacts.

OPTION B: There is a very good chance that you are seeing the effects of a hijackware infection.

Also available via the Consumer Security Support home page:


1. See if you can download/run the MSRT manually:

NB: Run the FULL scan, not the QUICK scan!  You may need to download the MSRT on a non-infected machine, then transfer MRT.EXE to the infected machine and rename it to SCAN.EXE before running it.

2a. WinXP => Run the Windows Live Safety Center's 'Protection' scan (only!) in Safe Mode with Networking, if need be:

2b. Vista or Win7=> Run this scan instead:

3. Now run a thorough check for hijackware, including posting requested logs in an appropriate forum, not here. DO NOT SKIP THIS STEP!!

I can recommend the expert assistance offered in these forums:,,,, and

If these procedures look too complex - and there is no shame in admitting this isn't your cup of tea - take the machine to a local, reputable and independent (i.e., not BigBoxStoreUSA or Geek Squad) computer repair shop.

Good luck!

~Robear Dyer (PA Bear) ~ MS MVP (IE, Mail, Security, Windows & Update Services) since 2002 ~ Disclaimer: MS MVPs neither represent nor work for Microsoft
~Robear Dyer (PA Bear)
Microsoft MVP (Windows Client) since October 2002

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