Run FEdit on your Macintosh and perform the following steps:
0) Press the mouse button in FEdit's Introduction window to remove the window from the screen.
1) Insert the Office System 1 disk into a Macintosh disk drive. FEdit displays a dialog stating that the disk is not a Macintosh disk and asks if the disk should be mounted or ejected. Select the MOUNT button.
2) Select OPEN VOLUME from the FILE Menu. Press the dialog's DRIVE button until the 'internal drive' message appears. Select the dialog's OPEN button. You should see a window titled 'internal drive' and showing a bunch of stuff in the window.
3) Select DISPLAY SECTOR IN HEX from the DISPLAY menu. The 'internal drive' window should now show an orderly arrangement of numbers 0 to 9 and letters A to F on the left (I call this the 'hex area' since it contains hexadecimal numbers) with characters on the right (called the 'character area'). See the attached screen image at the end of this document for a sample of this window. Note that the window's top contains several lines one of which reads "Sect: 0". This means sector 0.
4) Select the window's horizontal scrollbar 'page right' arrow until the SECTOR information at the top of the window changes to 'IC' (hex for 28).
5) Select HEX MODIFY from the EDIT menu.'"""Hex modify active"""' should appear in the menubar.
6) Use the mouse to click on byte at location $CC (hex) in the window. This byte will be located in the row labeled CO and four bytes from the right of the window's hex area edge. In the sample window f igure this byte contains the value 00, the three bytes to its right contain 011517 (hex).
7) Change the bytes at locations $CC to $CF to be all zeros. Just type the zeros using the Macintosh keyboard.
8) Verify very carefully that you have only changed the four bytes. If you chop any other bytes by mistake quit FEdit and start over.
9) Select WRITE SECTOR in the EDIT menu. Answer in the affirmative to FEdit's question about writing the sector back to the disk.
10) Quit FEdit using the QUIT command in the FILE menu.