Firefox regularly changes my default search engine back to Google

[jussimiossec]

My default search engine is DuckDuckGo by my own choice. Firefox however repeatedly changes it back to Google without my authorization. I do not know why - maybe it happens after updates - but this is not alright. I will be switching to another browser and this seems shady to say the least.

[Standard8]

In the past we have generally seen this to be a result of adware on user's computers. Typically it has been installed with another program, and periodically sets your search engine in Firefox to something else. If it is happening in Firefox, it is also likely to be happening in other browsers as well.

Maybe use something like Malwarebytes to check your computer for adware.