i responded to your previous post where you discussed this same issue. see this thread:
https://community.ccleaner.com/t/ccleaner-professional-skips-all-firefox-during-custom-clean/154829
for the third time, the problem is being caused by the ESET security program that you have installed, its “browser guard.”
aside from adjusting the settings for the ESET program’s “browser guard,” you probably can avoid having the problem by closing firefox yourself before running ccleaner.
you also could use firefox’s own tools, in firefox’s “settings”/“privacy and security,” to clear firefox’s history, to empty firefox’s cache, and to remove the cookies that firefox has accumulated.
setting firefox to block third-party cookies, which are labeled as “cross site cookies,” in firefox’s “enhanced tracking protection,” would take care of about 99% of the cookies that you are wanting to get rid of.
setting firefox to “delete cookies and site data when firefox is closed” should take care of the rest of the cookies that you are wanting to get rid of.
notice that, in ccleaner’s “options,” there are some settings for “cookies” that you want to save.
also, there is a browser-extension called “cookie autodelete” which removes cookies, unless you have it set to save particular cookies that you want to save. i use it:
https://addons.mozilla.org/en-US/firefox/addon/cookie-autodelete/