Problem

Yamaha Steinberg Thunderbolt Control Panel and dspMixFx AXR may show a warning message as shown below on exit.

Cause

With macOS 15 Sequoia, the behavior of the OS when closing applications has changed.
However, this does not affect settings changed in the application, and the application will work fine if it is started again.

Solution

Currently, there is no solution but it is planned to be improved through a future TOOLS update.