I'm trying to desactivate notifications : -Options / Environnement / General -> Background Process Notifications and disable 'Show taskbar notification'
Great solution! This worked for me too. I left a connection open all night that had an editor open, which had run some big queries. I did get a persistent "cancel currently running query" error, but was able to close the editor, open a new one, run a big query, and close Toad normally, without freezing or stack dump.
It's surprising this issue has been open for so long, without a response from Quest. Is Toad for MySql becoming an unsupported product?