Most expert users (not all) recommend against using registry cleaners that advertise “automagic” scanning and cleaning.

And before anyone says there are good cleaners out there like CCleaner (https://www.techjaws.com/free-pc-optimizing-and-privacy-tool/), I will say that CCleaner, and Eusing, are two exceptions that prove the rule. And, CCleaner and Eusing are two that DO NOT do registry cleaning “automagically”, but rather offer the user items to select and also will make a backup of the registry (essential) BEFORE making any changes. And there are a few others out there that operate on that same principle.

(CCleaner BTW is a lot more than just a registry cleaner…see Frank’s article linked above).

Still, in the hands of novices, registry cleaners can be a dangerous tool. When a novice user thinks their system is sluggish, the first place they go is usually to a registry cleaner advertised on Google, and they likely find “sponsored” links that lead to scams “guaranteeing” improved performance if they use their “Registry Booster”.

(And more likely the sluggishness doesn’t have anything to do with the registry, rather it’s maybe a driver conflict or too may TSR’s)

For example, if you do a search for the term “Registry Repair” you’ll notice that the paid listings all include sites that say “read our review” or “warning”, don’t download anything until you read this. That is a good indication of a scam because these “reviewers” get a good percentage of the take if the user clicks on a link leading to a registry cleaner in their review. In other words, their reviews are up for sale – and are not anything but thinly veiled marketing ploys for scams.

And even if you’re using a safe registry cleaner, if you see an item that is identified as one that can be deleted and have no idea what that registry line does, it’s probably best to leave it alone. I do clean my own registry from time-to-time (using CCleaner or Eusing of course), but if I see a line that I do not know precisely and exactly what it does, or perhaps did, I usually leave it alone.

As far as experts recommending against automated registry cleaners, I’ll cite one:

Bill Castner, an MS-MVP and an Aumha VSOP & Moderator of (http://aumha.net/) says – “It most certainly if done should not be automated.”  (http://aumha.net/viewtopic.php?f=62&t=28099&start=0&st=0&sk=t&sd=aMS-MVP).

Bottom line, I definitely wouldn’t let some software from a suspicious and dubious site have a free hand in messing with my registry.