Here's how i solved this sfc error; i won't go into details how exactly to do every step...don't ask me how to take ownership, load a registry hive, etc, google it.
You should do that only if you plan to completely uninstall Avast and replace it with something else! If you reinstall it, the sfc errors will be (sadly) back...
1. Uninstall Avast with
avastclear2. Remove every file with "avast" in it's filename (everywhere, even in winsxs); take ownership if Windows doesn't allow it.
3. Remove every avast reference from registry
4. Boot your pc with any WinPE service disc/usb that has regedit (i recommend Sergei Strelec WinPE, Hiren's Boot CD is also ok), load the COMPONENTS registry hive (it's in C:\Windows\System32\config, backup it first; you may need to take ownership and/or unmark it as read-only)
5. Remove ALL avast references from the loaded hive, close regedit, restore COMPONENTS file ownership (if you took it) and restart
6. Run
sfc /scannow and check if there are still avast-related errors; run
dism /online /cleanup-image /restorehealth too just to see if everything else is ok too.
I've used Avast for 10+ years, recommended it to literally everyone and was never disappointed until Win10 came...hours of wasted time with OS reinstalls on my and customer pc's because dism kept failing at 20% (avast locked it, would never suspect that), then those false sfc errors...