When attempting to complete the Health Check I receive and Egads Installation Failed message with error code 0x80040c01. What does this mean?
'Egads' is a message from Chrome, usually seen when a Chromium based browser fails to install/update. I'm not sure why you are seeing that in CCleaner?
0x80040c01 is a software update error, so I'll guess it's happening after Health Check has found app(s) to update and you clicked 'Make it Better'.
That particular error code can have many causes, so it can be hard to track down just what is causing it.
I suggest that in CCleaner you go to Tools>Software Updater and see what it finds to be updated.
See if software Updater can update it, and if it can then please let us know and we can flag up that Health Check may have a problem.
If Software Updater can't update it either then it shows that the problem lies elsewhere.
In that case I'd try opening whatever app was found to need updating and try using its own update button.
PS. If you use Custom Clean in CCleaner then it doesn't do that software check as standard, so that would avoid you seeing that error until you can work out just what's causing it.
You can set Custom Clean to be the default clean in Options>Settings>CCleaner Home Screen.
I am using win10/64 and ccleaner pro version 5.66.7716 (64)
I received the same error code, followed instructions tool>sofware updater and it installed OK. Program was Google Backup