Sierscmaster

Thank you, I will do what you suggested. In the end I still have an option to just format clean the drive and reinstall the system which could be usefull thing to do form time to time.

TrendMicro HouseCall also didn't find anything...

I will take a closer look at it tomorrow, Microsoft Safety Scanner took almost 5 hours to run and found nothing. TrendMicro HouseCall is in progress now.

Firefox is not crashing (no crash log, crash report or error in Windows event log), it's opening and closing right after very, very fast, sometimes even the "white window" didn't have enough time to appear on screen, so this is a different issue.

I used my licensed ESET Sercurity to scan once again the whole system with the same result - nothing found. Adobe Flash Player 25 NPAPI removed. Regarding Firefox extensions - I'm using ONLY Ghostery and uBlock Origin which are one of the most used extensions globally. Safe mode is not working on "default" Firefox and after changing the name to firefoxx it is working as intended without it. I already try at least 4 different fresh installation of Firefox: - uninstall + remove EVERYTHING from program files/appdata - reinstall - installing older version - installing beta version - installing to different custom location None of this fixed the issue I'm in the middle of Microsoft Safety Scaner now, I will update when it's done.

I changed firefoxx.exe to firefox.exe and it's still closing right after I clicked it. Workaround still working, so the issue persist. Fixlog.txt

Addition.txt FRST.txt

MTB.txt

I already did scan with ESET, nothing was found.

Yes I can use Edge and after my workaround with chaning firefox.exe to firefoxx.exe I can use it as well like before.

Hello, sorry to hijack the thread, but I have exactly the same issue. Same dates, same applications. If it helps I found out a workaround for the issue - changing chrome.exe and firefox.exe names to something different (i.e. firefoxx.exe) fixed it. MalwareBytes found nothing, I'm attaching the log files as well. Addition.txt FRST.txt AdwCleaner[C01].txt AdwCleaner[S01].txt