After troubleshooting and process of elimination, I have discovered a setting that is related to Ccleaner crashing, after a recent update to version 5.27.5976. When the Firefox Compact Database cleaning option is selected, it freezes/crashes at 96%. I have had this selected through several updated with no issue. This issue does not occur while cleaning Chrome's compact database.
System: Windows 7 32 bit
Firefox version 52.0 (latest version which has eliminated support for NPAPI plugins like Java and Silverlight).
Will there be a fix for this bug soon? Let me know if you need any additional information.