Copying from the private message that I replied to you on this subject, plus a bit more polish to the answer:
...this "Retry count" is when there is pending operation in Windows, as it states "Waiting on current system action".
Reboot the OS and it should be ok if TrustedInstaller does not run again by itself.
If it does, try configuring Features or updating Windows and rebooting, that pushes the TrustedInstaller to finally complete its pending operations.
If anyone knows a better way to push this, let me know and I'll automate it, sometimes annoys me as well during live editing (C:\Windows).
Btw if editing C:\Windows, try to avoid configuring Features in the same session, that's mostly the issue, needs to reboot to continue.
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Regarding the updates, what do you mean, to implement UUP listing and download or?
There are Release/Preview updates listed already when available in the Microsoft update catalog, just not those exclusive to UUP, we don't need one more insecurity during testing, let Microsoft fix its own bugs first.
