There's nothing really wrong with Reg Organizer 9.01, but I'll pass because of the messy installation. It adds folders, many with tiny files, everywhere. In addition to the program's folder, a folder's added to C:\Program Files\ WindowsApps\, 1 folder in ProgramData, 3 in ProgramData\ Microsoft\ Windows\ AppRepository\, 1 in ProgramData\ Packages\, 1 in Users\ [UserName]\ AppData\ Local\, 1 in Users\ [UserName]\ AppData\ Local\ Packages\, 1 in Users\ [UserName]\ AppData\ Roaming\. I recorded 324 new registry entries in my Win11 VM.
Registry cleaners are IMHO a matter of personal preference -- some swear by them, while others loath that type of software. Either way they can delete known bad or useless keys, and they search the registry for orphans, links to missing files or other registry entries or keys and delete them. Some software is developed for years [maybe even decades], which often means old legacy code that no one may even remember. And that old code may require registry keys that are no longer used, and they may be rightfully deleted as orphans by registry cleaners. If so, that software breaks.
Registry cleaners as part of an uninstaller OTOH search for the software's name & delete those entries found. If you have the patience, it's MUCH more effective to search the registry yourself using Regedit. That's because the registry uses a hierarchical structure -- an entry may be buried several layers deep in a registry key, and deleting that key may remove a dozen lines vs. just the one line with the actual name of the app. Note however, you actually need to check all the keys and entries under a key to make sure nothing else is effected.
Uninstallers themselves most always do an incomplete job, because the rules they're based on have to always be 100% safe. Those that record changes during an install leave some things out -- the only app I could ever find that lists everything is an old program called InstallWatch Pro, which I use in VMs. Apps for converting software to portable versions *may* also do a decent job recording changes. The downside is that some software installations trigger rewrites of complete sections of the registry, meaning 50 or 60k, or more new entries to parse. Usually the changes you're after happen at the very tail end of these huge records, so it's not quite as bad as it sounds.
Reg Organizer bills itself as a file cleaner, but after running Windows Disk Cleanup followed by the Microsoft PC Mgr. beta it could not find anything meaningful in terms of disk space to delete. Of course mileage may vary. If you're after removing stuff like file histories & caches I recommend the portable KCleaner, a repeat GOTD -- does the same stuff without the overhead & mess.
