Error while trying to install 1607 update

When I try to install update 1607, I receive this: error 0x8024201c

Any ideas?

Two things:

Are you running any extra Anti-virus, anti-malware, firewall, anti-anything programs? If so, disable or better yet uninstall them and try again.

Open a Command Prompt (Admin) [from right click on the start icon] and run:

sfc /scannow

Do you get any errors from that?

NavyLCDR said:

Two things:

Are you running any extra Anti-virus, anti-malware, firewall, anti-anything programs? If so, disable or better yet uninstall them and try again.

Open a Command Prompt (Admin) [from right click on the start icon] and run:

sfc /scannow

Do you get any errors from that?

Scan failed at 23%

I only have the Defender which is disabled

sfc failing means you have corrupted OS files and/or permissions which is causing the issue. If it were my computer, I would create a new Windows 10 installation USB flash drive or DVD from the latest (ver 1607) ISO file from Microsoft and do a clean install. That will help guarantee you won't have problems with future updates.

But - if you want to try to fix what you have now, you will need the correct ISO file that matches the major build number you have now (probably either 10240 or 10586), here is a good tool:
Microsoft Windows and Office ISO Download Tool

Once you have the matching ISO file you can try a DISM repair:
https://www.tenforums.com/tutorials/...-10-image.html

Or a repair install:
Repair Install Windows 10 with an In-place Upgrade