I have W10, Firefox Browser, WLMail client.
Kindly let me know how to stop a ccleaner popup telling about closing or cleaning my browser! It's terribly annoying as it appears many times a day. Thanks ever so much!
You must have all the browsers exited when you clean, so whichever browser it it telling you to close is still open, maybe only as a background service (such as cloud print) or as an errant process which isn't/can't closing/close properly; check in task manager.
If you have monitoring on turn it off then you can clean manually instead.
How to disable system and active monitoring
https://www.piriform.com/docs/ccleaner/ccleaner-settings/changing-monitoring-settings-ccleaner-free
If you want to run CCleaner without closing down your browser, then check the box shown in the following screenshot ...
Just remember that the browser won't be cleaned until it's closed down and CCleaner is ran again.
If you ever want to undo that option, that can be done by using the CCleaners "Save all settings to INI file" checkbox in "Options\Advanced".
Then open the INI file in CCleaners "Program Files" folder by double clicking it, and alter the "ShowFirefoxCleanWarning=False" to "ShowFirefoxCleanWarning=True", or the entry for whichever browser you use.
I don't know of an easier way to do it.
Hope that helps.