On three on my Win7 systems, clicking on the Cleaner button will cause the Analyze button to immediately be active. On my desktop, it can take up to a minute for it to be active. The 2 desktops and a netbook have Win7 Home and another laptop unfortunately has Win 10. Clicking on the Registry button does not have the lag. Any idea why? It's been happening since at least version 5.09. I'm using 5.40.6411
Bump
You are using an old build of CCleaner. Try uninstalling it, restarting machine and then downloading and installing the latest build from here
I have the latest version, just downloaded today (May 31). Same problem.
I remember having a similar problem a while ago (about version 5.30 to 5.33 ?), but mine was a bit more severe and the buttons stayed greyed out until I force closed CCleaner.
I captured some debug logs and it seemed to be an issue with CCleaner trying to check for updates but not making a connection.
Try turning off your internet connection (flight mode if you have it) then running CCleaner and seeing if that stops the lag happening.
CC should recognise that there is no internet so won't try to look for an update.
It's not a regular workaround, but it would point out if that is the issue here.
EDIT-
You could also try unticking Options> Settings> "Inform me of updates to CCleaner", to see if that makes any difference.
(But I think that it still checks, just doesn't tell/bug you if it finds one).
Fixed problem
Uninstalled Ccleaner using Advanced Uninstaller 11 (v12 sux). Installed latest version of Ccleaner. It works now. So far.
that's good news.
glad you finally got it working.