argh no ... it's back! The macOS freeze when an external monitor is hooked up

macuseramsterdam wrote:

After upgrading to Catalina a while ago my machine started freezing. Turns out this was a common problem as many users with an external display reported this, especially once the screen saver kicked in the likelihood of a freeze and the dreaded watchdogd timeout increased.

And of course I was so naive thinking Apple would not let that happen again. But this time it's even worse - after installing 10.15.4 the machine will very reliably completely freeze within about 15 minutes when hooked up to an external display (and eGPU), also when not idle/no screensaver.

When not hooked up to the external monitor it looks like things are working.

Verify you also installed the supplemental

Download macOS Catalina 10.15.4 Supplemental Update https://support.apple.com/kb/DL2038?locale=en_US

Customer support Call (800) MY–APPLE (800–692–7753)