How to delete files owned by SYSTEM

I use Unlocker and I never regretted it.
Install it, right click on a file or folder and you'll see the Unlocker icon.
There are a few options, it can unlock instantly or the file will be automatically unlocked and deleted after a system reboot.

On the author's web page isn't available anymore so download it from Major Geeks.

On the author's web page it says compatible up to Windows 7 but Major Geeks page says up to Windows 10.

Download Unlocker - MajorGeeks

UNLOCKER 1.9.2 BY CEDRICK 'NITCH' COLLOMB

IObit has a similar utility and I assume they bought the license from the original author.

I had a problem with icloudhome running up CPU and needing to kill it via task mgr. but it would always restart. under apps it had been uninstalled but the icloud folder had all the files still and kept loading itself. I couldn't delete the file I would get the 'file onwed by SYSTEM' message. I used one of the recommendations to install Emco Unlockit (free). It worked super fast, I unlocked and then delete the whole folder.

Rather than hunt down the problem ... why not just skip Adobe and use one of the many other PDF tools?

I use PDF-XChange Viewer.
Many people seem to like Foxit Reader.