hello, everyone, i posted this yesterday, and got a bunch of replies that were a little off-topic. i appreciate all who responded, but i just want to clarify a few things to avoid confusion: 1. i have been using computers for a long time. 2. i am using a mac. 3. the only change in my system recently was installing the new firefox update a couple days ago. 4. i know how to use malware scanners, and do so. 5. please read the details below before responding, if you are inclined to help. thanks again, i don't mean to seem rude; i just want to avoid numerous replies suggesting that i try something that i already tried, as in the description here: this is the first time i've ever had an issue with firefox. i updated to 77.0.1 thursday, and yesterday i woke my computer from sleep to discover a warning about possible ransomware. it told me there were 6 cache files possibly compromised, and i chose to restore them from previous copies when asked. then i got the spinning pinwheel, and had to force close firefox. when i tried to open it, it kept saying 'The application “Firefox” can’t be opened.' i deleted firefox from apps folder, then downloaded and reinstalled; same thing happened. ran profile manager from terminal window, created new profile, it opened and seemed ok. closed it, then it would not reopen, same error. so i deleted app again, reinstalled again, no good. ran profile manager from terminal window, selected newly created profile, opened it ok. closed it again, wouldn't reopen. i'm on a 2016 macbook pro, osx mojave 10.14.6, set to auto-update apple security patches; also using bitdefender and malwarebytes, auto-updating and running in background at all times. did a manual system scan; no malware. i am wondering if anyone else is having this problem. i've been using firefox for many years, glitch free. now i get the new update, and it's being weird. one of the first recommendations for crashing issues is to reinstall the OS. i'm not going to do that, that seems seldom to solve the problem, and i have a complex installation. far less hassle to switch to a different browser. if anyone has any ideas that do not involve scrubbing my laptop, please let me know.