Apple Macintosh System 7.5 - Manual (Page 100)

The floppy disk drive on your Macintosh Plus, Mac SE, or Mac II doesn’t recognize the
installation disks.
Problem: When you try to begin installation, your computer does not
recognize the installation disks.
Cause: The floppy disks are 1.4 MB disks. System 7.5 components are not
available on 800K floppy disks.
Solution: Install System 7.5 components using a CD or install over a network.
Problems using System 7.5
This section helps with problems you might encounter using the computer
after you have installed System 7.5.
You can’t start up the computer.
Problem: When you turn on your computer, you see a “bomb” message.
Cause 1: You probably have an incompatible item in the System Folder.
Solution 1: To turn off potentially incompatible items in the System Folder,
hold down the Space bar while you restart your computer. When the
Extensions Manager opens, choose System 7.5.3 from the Sets pop-up menu.
Close the Extensions Manager to resume startup. All extensions are turned
off, except those for System 7.5. Once you have started up the computer, you
need to determine which startup program is causing the problem. For
instructions, see Appendix A (“Testing for Compatibility”) later in this book.
Cause 2: You may have damaged your system software.
Solution 2: Follow the instructions in Appendix A (“Performing a Clean
Install”) to reinstall system software.
92 Chapter 7