"The problem that I'm encountering is that the sound input is now always in Playthrough mode, and I can find no way in Mac OS 8.1 to turn it off."
"There seems to be a problem introduced by 8.1 on 7100 and 8100 Macs. The Sound input source is being reset to Microphone each reboot (even when no microphone is attached)."
Update: Gary Wong writes: "The Monitors & Sound Control Panel may save its settings in its preferences file but, on the 61/71/8100 class machines, read the preferences from the Sound Preferences file."
"I got the error message suggested from the Read Me files (e.g., when using Apple Speech Recognition version 1.4.1 software on some computers). Following the advice listed there, I tried to select Sound In as the source, since PCI machines do not have Microphone as a selection, and the source is switched back to None upon restart. An error message still appears and I must open Monitors & Sound to reselect Sound In every time."
Weird sound at startup Several readers are reporting a "high-pitched" or a "loud and continuous" sound that persists during startup or immediately thereafter. It stopped if they get the Mac to make another sound (such as "by opening the Monitors & Sound control panel and clicking on one of the alert sounds").