Can’t guarantee that this problem was CIS however after many attempts to get insider build 16179 to install and receiving the error 0X80070020 at each attempt, even after rebooting more than once, when I stopped CIS AV the build went in first time.
The last two digits of the error code is 0x20 which does mean ERROR_SHARING_VIOLATION: The process cannot access the file because it is being used by another process. And you have this microsoft article that suggests to temporary turn of anti-virus software.
MicroSoft has made some underlying changes in preparation of new features coming on the Developer’s Build (next public release).
I certainly hope Comodo has these addressed sooner than later, or we will all be going through the same issues again we are now.