'Suppress Endnotes' option unavailable when no endnotes due to design.
Cause:
The 'Suppress Endnotes' option is not enabled unless the endnotes are designated to be printed at the end of each section.
Solution:
Designate the endnotes to be printed at the end of each section.
1) Insert the endnotes.
a) Select the 'Insert' menu and select 'Footnote...' (The Footnote dialog box appears.)
b) In the 'Insert' group, select the 'End note' radio button.
2) Designate the endnotes to be placed at the end of the desired section.
a) Click 'Options...'. (The Note Options dialog box appears.)
b) In the 'Place At' drop-down list box select 'End of Section'.
c) Click 'OK'.
3) Click 'OK'.
4) Suppress the endnotes.
a) Select the 'File' menu' and select 'Page Setup...'. (The Page Setup dialog box appears.)
b) Click the 'Layout' tab.
c) Select the 'Suppress Endnotes' check box.
d) Click 'OK'.