Pokki Start Menu - SweetLabs Inc.
It will install on Windows 10 too, and personally I would want rid of it. Their 'helpful' utilities collect information from your PC activity, pass it back to their server, and channel adverts back to you. It should be safe to uninstall it via Control Panel, start menu should revert to the standard windows 10 menu.
If you are still using the standard windows 10 menu, it is possible that your antivirus may have already performed an incomplete removal, hence the error messages. If Malwarebytes doesn't shift it, try Superantispyware, one of them should remove any traces of it as a PUP - potentially unwanted programme.
Sweet Labs have been around a long time, and their adware/spyware has been a constant pain in the neck. They are usually bundled with other programmes, with an easily overlooked tick box to opt out when installing the intended software. The included uninstallers often leave bits behind, or fail to work at all. I can remember SweetLabs causing me grief back in Windows XP days!