We have recently learned that people who’ve installed CCleaner may lose the saved settings of Firefox extensions they have installed after upgrading to Firefox 79.
This is due to a recent update in Firefox that creates a new sqlite file and two supporting companion files within your profile to store synced extension data. When you run Firefox 79 for the first time, your extension storage data is automatically moved to the new file. CCleaner does not recognize the two new companion files and deletes them, which causes your extension settings to be lost.
We’ve notified CCleaner of this issue and on August 6, 2020, they made an update that will fix the problem. The update will be automatically applied to paid users. If you are not a paying CCleaner user, you will need to manually download the update from https://www.ccleaner.com/ccleaner/download/standard. The release notes for this update are available at https://www.ccleaner.com/knowledge/ccleaner-v5707909.