MinimServer: no valid content directory found

[simoncn]

My apologies for not noticing that you had already tried delaying startup by 15 seconds.

I think this means you need a longer delay time. Please try increasing the delay time to 60 seconds to see if the music SSD is available after this time. If this works, you can reduce the time to find out how much delay is needed. How is the music SSD attached? Is it a USB connection?

Also, I think your other suggestion of putting the music library on the system SSD should solve the problem.