Symptom
When setting up a serial printer in the Chooser to use the printer port, an alert box with one of these error messages appears: "port in use", or "port currently in use by another application", or "port already in use".
Solution
Reset the printer port by doing the following:
1. Open the Chooser from the Apple Menu.
2. Click Inactive.
3. Restart the computer.
If, after restarting the computer you see the same symptom, make sure AppleTalk is Inactive in the Chooser, and then reset the parameter RAM.
Resetting Parameter RAM (PRAM)
1. Restart the computer.
2. When you hear the startup sound, press and hold down simultaneously the Command-Option-P-R keys.
3. Continue to hold the keys until you hear the startup sound four times.
4. Let up on the keys. The computer will finish restarting.
5. Open the Chooser from the Apple menu.
6. Click Inactive.
7. Restart the computer.