Apple Macintosh System 7.5 - Manual (Page 71)

To use the Extensions Manager during startup, hold down the Space bar as
you start up the computer. The control panel opens during startup to allow
you to turn extensions on or off. When you close the Extensions Manager,
your computer resumes starting up and loads the extensions you selected.
Find File
Find File lets you enter a list of specific search information to find a file. You
can look for the file based on information such as location, name, size, date
created or modified, and version.
To find an item, open the Apple (K) menu and choose Find File.
63 What’s New
To begin the search,
click Find.
To choose search criteria, click the triangle and
choose from the pop-up menu.
To turn off an extension (prevent it
from loading), click it to remove the
check. To allow the extension to load,
click it again to put a check beside it.
Grouping extensions into sets allows
you to turn them on or off as a group.
If you think you have a problem with
incompatible items, open this menu
and choose System 7.5.3.