Logic Pro has a bug that can happen where the control surface has one-way communication. The faders don’t control Logic, but moving a fader in Logic will move the fader on the surface. It happens because Logic Pro tries to use network port 7000 which is already in use by another application. We have reported this issue to Apple. They acknowledged the issue but have not fixed it yet.
V-Control Pro 2.8.1 shows an alert dialog if it detects an application besides Logic is using port 7000.
You can work around this issue by determining which other application is using port 7000 and stopping it.
Please try these steps:
1. Reboot the Mac computer and try again. This might solve the issue because the other application will not have started yet or it will not be using port 7000.
If the problem persists, try this:
2. Open Terminal. Enter the command “lsof -i4UDP:7000”. And Enter the command “lsof -i6UDP:7000”. This will tell you which applications are using port 7000. Try to quit the application that is using it. It might be a process that you have to locate in Activity Monitor and force-quit. Some users have seen this happen with a Waves application.