Defining a handler for a property change signal, and then setting a break point in that handler is my usual technique for finding unwanted changes.

Hi, to get that missing the driver dll (ibmysqlclient.21.dylib) perhaps you have not installed MySQL on your Catalina PC? For more see here

@Sam-Aaron said in QtMultimedia - UI Freezes after 6.4.0 update.:

Downgrading to Qt 6.2.4 does appear to have fixed the issue. I've had the GUI running overnight and all morning and no freezing so far.

Unfortunately (for me) this assertion was wrong and I got a freeze with a Qt 6.2.4 build. Apologies for the red herring - my issue is likely unrelated.