Hi, Thunderbird updated itself on my machine on Thursday last week to 78.4.0 (64 Bit). My machine is running Mac OS X 10.15.7. I have multiple profiles on Thunderbird for different email accounts. All of them open and migrated without problem with the exception of one profile (As Murphy Dictates the most important one). I have tried starting Thunderbird in Safe Mode, starting with plugins disabled etc and they all deliver exactly the same result that Thunderbird hangs and does nothing although it does show mail folders etc before it hangs as per the attached screenshot. If I try to leave it open and running I eventually get a message on the computer that the computer is running out of memory as Thunderbird is using 55GB of Ram. The main Thunderbird screen opens as you can see in the screenshot but then just a spinning ball. Does anyone have any suggestions other than the normal safe mode startup or disabling plugins as I have exhausted all the normal routes. Thanks, Mike