I started originally in programming Apple II, Lanier NoProblem, & Tandy. I have been a network admin since 1986 on NetWare, Windows NT, Windows 2000 & Windows 2003. I install networks & workstations & am responsible for all program & updates from DOS 3.2-Windows 3-Windows 98A, Windows XP thru Windows 10. I am intimately familiar with the Windows registry on all Microsoft products. Programs that boast registry cleaning flood the Internet. Generally, I use Symantec/Norton products to limit unnecessary entries in the registry. Occasionally I use third-party utilities to find hidden keys in binary etc.
A strong word of caution is if you are not familiar with registries, stay away from registry cleaners. It's okay to defrag or compress it but not to delete entries. I eval this utility by running on a virgin Windows 10 Professional system that I had only installed Windows Updates and perused the Internet with IE & Edge.
When I ran WRC, it returned over 1000 problems. Now it was okay to identify IE & Edge temporary files but it also wanted to delete or modify other important entries. All ActiveX/COM/BHOs are not bad, although some may be & they are regularly ill referenced everywhere you look. If you know how to use MMC &/or browser add-ins management, you don't necessarily need a third-party util. The firewall can be managed from Control Panel, MMC or Admin Tools. If you don't like Control Panel, Windows Services can be managed from MMC &/or Admin Tools under All Programs. The point here is: Know your OS well enough to utilize embedded controls rather than auto-repair. You will almost assuredly disable important functions & disable your system functionality if you go blindly changing things.
This program disabled us from uninstalling applications. Applications attach themselves to "file types." If the file type is deleted, does it recreate the file type? Who knows but the programmer ! I could go item by item, but I think I've made my point.
So, how do you protect yourself you ask. First, make a backup of your registry from within the registry, second, create a Restore Point from within Computer Management, third, make another registry backup from within WRC. It also includes a "Restore Registry" function.
Start slow. Change only one category, reboot, test your browsers & any important/useful apps. Beware of binary keys ! Change only categories you recognize the format. Always reboot after ANY registry changes.
I am not condemning the software. I think a lot of Wise apps, but I know what I am doing as well as the risks. I wish you the best of luck & hope you will find their utilities as useful as I have, & will purchase their suite for what it's worth to you.