Which version of CCleaner were you installing? v5.40.6411 (64 bit)
At the time you installed CCleaner, had you restarted your computer in the past 30 minutes? No
Did you use any of the Custom Installation Options in the CCleaner installer? Yes
Which product version and edition of Windows are you running? Windows 7 Home Premium 64-bit SP1
If Windows 10, do you have the Creators Edition update? N/A
If known, what is your operating system architecture? 64-bit
Which malware/antivirus applications did you have active?
Windows Defender
Malwarebytes
Avira
Which internet browser do you primarily use?
Firefox