How to get rid of - for good - MacKeeper from my Mac?

https://mackeeper.com/uninstall_mackeeper/

It's a pretty nasty piece of software, you may have to use FindAnyFile and search for MacKeeper and then manually trash everything FindAnyFile can find on the app. You also may have to do an erase and install to start over and then manually restore your data files from your backup and manually install each of your third party apps.

Going forward NEVER EVER install any antivirus, cleaning or any third parties "maintenance" apps unless you want to experience similar problems!!!!!!!!!!!!

Did you install MacKeeper at some time or are you getting popups about MacKeeper?

If the latter Download and run Malwarebytes and run it in the free mode.

It was developed by a long time contributor to these forums and a highly respected member of the computer security community.