With cleaning apps on GOTD the last couple of days, thought maybe this might help &/or be of interest. That, and because the misinformation/disinformation that always appears in the GOTD comments bugs me. Windows does break, often enough on its own, without you doing anything like installing software, or in this case, cleaning the registry, so if you consider Windows breaking to be a problem, Back it Up! You can treat Windows like a toaster, replacing [reinstalling] it when it fails, or you can invest at least $25 [~$20 for a 120 GB SSD & ~$5 for a USB case] and usually about 10-20 minutes a day or week or whatever to back it up. So, if you’re worried about breaking Windows or software by working with the registry, make sure you’ve got a good backup & have at it -- or just do the toaster thing. I won’t insist either way is right or wrong, so PLEASE, DO NOT insist your way is the only right way to do things.
[Some folks seem to take the stand that Microsoft is GOD-like, never errors, and that Windows, including the registry, is somehow bulletproof. Really (!)? Truth is, Microsoft has been promoting the toaster analogy, more quietly with Win7/8, but quite loudly with Win10 – if you can get to the Win10 boot menu, it’ll now even download the files for you to repair/reinstall.]
For privacy, the best way forward is to use a VM [Virtual Machine] running either Linux or an un-activated copy of Win10 [IMHO the Ent. Version’s best because it won’t prompt you to activate]. Once it’s set up, copy the VHD [Virtual Hard Disk] with the VM itself to a backup location, then after using the VM, replace the copy that was just used with a copy of the original you stored. That way there are zero records of that session or sessions. If you want to store new data in that VM, you can create it with that VHD on a microSD card that can be hidden most anywhere, &/or easily destroyed, or use VeraCrypt to encrypt that VHD. VeraCrypt also has an option to create a hidden VHD within an encrypted VHD – the password you use when unlocking either gives you access to the *public* VHD, or the hidden, secret VHD.
To protect your online privacy a VPN hides your IP address, though be aware that many VPN services do keep logs. There’s also the free TOR browser that routes your traffic through several anonymous proxies to hide your IP address, though it’s obviously going to be slower than a regular connection. The VirtualBox VM host software also allows you to very easily, and optionally randomly, change the MAC address for the network adapter, which is sometimes used to ID the exact device you used to go online. The major web browsers let you limit cookies and other means of tracking, though that can compromise how web pages work, while privacy modes prevent storing any of that sort of data when the browser’s closed. There are also portable versions of browsers like Opera & Firefox that limit what’s written to disk in the first place. You can use the regular version of those browsers to semi-permanently store data like cookies to frequently visited sites, where that stuff can come in handy, and use the portable version otherwise, or just start the regular version of that browser in privacy mode when visiting other sites.
Lots of apps offer to clean up afterwards, but it’s less efficient that not having anything to clean up in the 1st place – why bother with a 2nd step cleaning up when you can avoid that step entirely? A somewhat similar strategy is to use fake data that you make up when you register just about anything, from web sites to Windows. When you install & activate one copy of Win10 on your device, a second copy should activate automatically, but can use whatever log-in or account you like, including one using fake data. Using that copy, whatever data Microsoft for example might collect will be connected to that fake data/ID, if in fact it’s not all anonymized as Microsoft states, though the machine ID & IP address will still be the same, so it’s not entirely bulletproof.
AS for Windows health itself, Windows has always collected garbage, growing in the process. I keep things clean one, because I tend to like things somewhat neat & tidy, and two, because it reduces the size of Windows’ foot print, and makes backup archives smaller – it’s simply more efficient use of storage, which is always of limited capacity. Smaller backup images also take less time to create and restore. Whether you actually *need* to clean up in Windows depends largely on what you do – your behavior. If you don’t install lots of software, Windows will only grow from updates, and unless the software you do install has problems, you probably have no actual need to clean it, ever. Do note however that I’ve sadly experienced all sorts of problems from software, including drivers from major companies like Intel, so there may be times when cleaning up is really unavoidable.
If you goal is to limit the disk space used as much as possible, getting rid of temporary files is usually less important than you might imagine. Using the System Files option running Disk Cleanup after a cumulative update in Win10 usually gets rid of 1 GB or more of unneeded junk. If you want to keep the amount of storage used on the Windows partition in Win10 to a minimum, move most of your files to OneDrive or relocate them to another disk or partition. Folders like Pictures or WindowsApps [where your Store apps are located] can easily be moved to another disk or partition, while software like Nero can include LOTS of content files [over 1 GB] that can sometimes be located elsewhere. And a lot of software stores installation and/or update files in the ProgramData folder, and less often in Windows\Installer. Sometimes that stuff is needed for uninstalling the software, and in that case if you do move them it can be best to store those files elsewhere in case you have to put them back, but very often that’s not the case. The Logitech G Hub software is a great example – every update stores a new copy of the setup files in ProgramData and does not delete the old ones. Since those setup files get uncomfortably close to 1 GB each, whenever there’s an update I uninstall the app, then reinstall just the latest version. That’s saved me as much as 6 GB over the course of a year. One folder to keep an eye on is: C:\Windows\ SoftwareDistribution\ Download\ -- it can sometimes grow to close to, or even over 1 GB, and can safely be deleted when it does.
If you’ve got Restore Points enabled, that takes up disk space too – before a backup I’ll go to Control Panel -> System -> System Protection, select the drive, then click configure to delete sometimes several GB worth of automatically created restore points. I use AMD hardware, and their driver updates always create a C:\AMD folder that can be deleted. Of course, there are the 2 Windows temp folders to be emptied – C:\Users\ [UserName]\ AppData\ Temp\ and C:\Windows\ Temp\ -- these are never emptied when you run Disk Cleanup (?). All the major web browsers let you delete any files [e.g. cache] that have been stored, usually in their settings menus. That all said, sometimes a cleaning app can help get rid of something you missed, e.g. KCleaner got rid of ~6GB [if I remember correctly] in the ie cache that I could Never get rid of.
So much data is stored in the registry that I’ve always been dubious whether any cleaner could ever get rid of everything that might be privacy related, and deleting an app’s list of last used files has seemed more inconvenience that it’s worth to me [but then I’d never do anything naughty outside a VM]. Reducing the space that the registry takes up had been important on a copy of Win7 I had that was over 7 years old and had seen duty on 3 or 4 incarnations of this PC. With Win10 being replaced at least yearly that hasn’t seemed much a problem at all so far, though I imagine if I installed lots & lots of software it could be. Bear in mind that device horsepower varies widely. On this PC, including with Win7, I’ve been running mid-high range CPUs, with 8-16 GB RAM, so reading, parsing, writing the registry in RAM hasn’t been nearly the problem it is on my wife’s convertible with a lowly Intel i3. It *might* be even more of a problem with Win10, given the way that Microsoft has engineered Win10 to work better on very low powered, budget devices, trying new stuff with memory management that may not always work quite as intended. Microsoft for example introduced a new technique with the Chromium-based Edge browser – Google enabled it in Chrome, and promptly disabled it again finding in their opinion nasty side effects.
Repairing the registry can really only be done manually – if a registry cleaner fixes something it’s more luck than intent. Unless you have specific directions for whatever task you want to perform, it can also be Very daunting. I’ve had to clean out registry entries associated with a program several times, and at the least it involved searching for the app’s name and that of the publisher, searching on the names of any .exe files, recording and searching on any keys or IDs in every entry found, and I’ve had it take more than a good day’s work. When you start Windows Regedit, you’ll see a hierarchical structure with sections, keys and subkeys, both containing entries. Some of those entries include the name of another registry key, e.g. a CLSID, and some include a file name or names. Registry cleaners typically find entries where the referenced key &/or file do not exist and propose deleting them. It’s less efficient because sometimes the entire key, with any additional subkeys and entries can be deleted, but that takes a human to decide, so the software will only delete the found entries. But it’s Much faster than doing it yourself manually.
Obviously removing a broken link in the registry shouldn’t fix or break anything – it just reduces the size of the registry because it no longer has to store those entries. But it’s easy to find reports where registry cleaners have done just that. The most likely reason is that whatever software required a broken link to be there, and when something’s fixed, it’s because it was that now broken software that was causing the problem to begin with. Why would software require a broken link in the registry? Probably because some coder had the software check to make sure it existed. It might have been a [much?] older version, but the check for that entry was never removed.
Lastly, apps like Cleaning Suite Pro also offer to help with software set to start with Windows. Yes, that can be a problem – between software and just normal Win10 services firing up and doing their thing, on our lower powered devices [a couple of tablets, an i3 laptop, a Celeron powered NUC] fully starting Win10 takes a Looong time. [By fully started I mean resource use in Task Mgr. drops below ~75%] Most of those auto start 3rd party software processes &/or services are for convenience, e.g. either checking for updates or starting some processes so opening that app happens quicker. Assuming you can check for updates yourself, and are willing to wait a bit when starting whatever app, most of those auto start items can be removed, or not, if the longer Windows start up times don’t bother you. Stuff that starts with Windows can be triggered several ways: there are 3 Run keys in 64-bit Windows registry, there are 2 startup folders in the Start Menu, unlimited tasks can be set in Task Scheduler, plus processes can be run as a Windows service listed in the registry.
Services are the hardest to manage… some are listed in Control Panel -> Admin. Tools -> Services, where they can be set to auto start, delayed auto start, manual, or disabled. If a service doesn’t appear there, it gets hard – you might have to search for and delete all related service & driver entries in the registry, which can sometimes cause Windows to fail to start. The easiest way in Win10 is Task Mgr. [right click the task bar]. The 2nd easiest is using Settings, which I prefer – something I believe is undocumented, turning an app off from auto starting in my experience reduces its priorities, reducing or eliminating problems, but does not stop it entirely from auto starting. I’ve got the 3 Run keys bookmarked in Regedit, so it takes just a minute or 2 to backup & delete an entry, but when an app uses a scheduled task or is in the Startup folder [hidden in Win10’s Start Menu] it can take a short while, so I can see where some would rather use a 3rd party app to manage that. I no longer recommend Sysinternals Autoruns… it can potentially be too dangerous. Autoruns shows you everything starting with Windows, and then some. Each entry has a checkbox, so you can turn whatever off – it relocates that registry entry to a new, non-referenced key. Listing both Windows and 3rd party processes, it’s easily possible to break Windows, full stop. [I use Autoruns, but use the built-in Jump to registry key, and then search for duplicates as well as deleting that one key, e.g. for drivers you usually have more than one, and failing to delete them all almost guarantees you’ve trashed Windows.]