I would leave the reg. keys were they are.
You could use Revo, either by reinstalling CCleaner and removing it with Revo,or by using Revosâ Forced Uninstall mode to remove the reg keys.
But there is no issue with simply leaving the registry keys there, they donât make any appreciable difference to the size of the registry or the functioning of a machine.
Most computers have many left over or orphaned registry keys, they donât affect anything.
On the wider topic of using the CCleaner Portable as a non-installed app:
I think that the issue here with Portable vs Installed is mostly a naming confusion/missunderstandingâŚ
(OK as well as a lack of developer consideration about the user downloadable CCleaner portable).
Some people donât like to install apps, instead they prefer non-installed apps.
Fair enough that is their choice to make.
However they do often have a tendency to call any app that can be used without installing it âPortableâ, and that isnât strictly true.
Such apps rarely if ever call themselves âPortableâ, they generally refer to themselves as ânon-installedâ.
Whilst non-installed apps can indeed be used in a portable manner, truly âPortableâ apps are not meant to be on a computers drive(s) at all.
Truly âPortableâ apps are meant to be on a removable drive/USB stick, and only be attached to the machine briefly to do a job and then removed again once that job has been done, leaving no traces of themselves behind.
In that respect the CCleaner âPortableâ that you can download is a kind of halfway house.
The true CCleaner Portable is the âTechnicians Editionâ a paid for version used for cleaning up endpoint computers in an organisation/business.
The one you can download from the builds page is more in the way of a favour for home users.
I believe that it was first created in response to user requests for a version that could be used on family and friends computers without having to install CCleaner on them.
Itâs intended to be used as the Free version, because the Pro features generally need CCleaner to be installed on the machine.**
So itâs a modification of the standard version, and some of the newer features in CCleaner are less amenable to such modification.
If you do use it as intended in a portable manner on family/friends computers then that isnât really a problem.
The CCleaner is on your stick not on their computers drive, and if it leaves a few reg. entries behind after use then so what, CCleaner isnât there to read them.
As said above they donât make any appreciable difference to the size of the registry or the functioning of a machine.
Itâs if/when you put it on a computers drive that it will then read those reg entries and begin to behave like the Standard version.
**Automatic Updating used to be a Pro only option so would never happen to a portable Free that was put on a computers drive.
But now that Auto Updating is in the Free version too that behaviour has changed, and a portable Free put on a computers drive can auto update itself and install the update, as you found out.