When i opened eM Client on Mac Tahoe i got an automatic push of upgrade to V10.4.5608 but after the upgrade my iCloud IMAP account app password became invalid.
So had to generate a new app password in the Apple account which fixed the problem. Never had this problem before with previous eM Client Mac upgrades.
Historically I have experienced issues with AUTOMATIC upgrade
to the point where I simply do not trust the PuSH that I have
disabled and now ONLY upgrade when I choose, always with eMC
shot down because I believe this is similar to the need to shut
down eMC manually before a system reboot or shutdown.
Since adopting this procedure I have never experienced any
failures; I also do not start eMC automatically on system boot.
I do this with Windows & Mac
skybat
¡Buena suerte!
¡Saludos desde Valencia la soleada en España!
¡Mis mejores deseos y mantente a salvo!