If you use the same port to alternately connect to a LocalTalk network and a serial printer, the port is not always correctly released after you turn off AppleTalk to use the printer. If you have trouble printing after turning AppleTalk off, restart the computer.
If you have experienced other issues since installing Mac OS 8.5 please read the About Mac OS 8.5 Read Me and Installing Mac OS 8.5 Read Me that come with Mac OS 8.5.
This information is from the Tech Info Library Article 58129: "
Mac OS 8.5: About Mac 0S 8.5 Read Me".