Display the Library window.
From the Edit menu, select Spelling, and then select Spell Check Library. Or, press 
+Y.
EndNote uses the Mac OS X spell checking feature. You can spell check your entire library or a specific reference.
Even when you use a spell checker, it is wise to read through the text yourself. If you type "fine" rather than "find," it will not show up as a misspelled word because both are valid words found in the dictionary. The spell checker cannot point out misused words or words that are out of context.
To spell check your entire library:
Display the Library window.
From the Edit menu, select Spelling, and then select Spell Check Library. Or, press +Y.
EndNote will open and check each reference. When a misspelled word is encountered, it is highlighted in the reference and a Spelling dialog appears.
You can stop the spell-checking process at any time by clicking the close box on the Spelling dialog.
To spell check a specific reference:
Open the reference you want to check.
From the Edit menu, choose:
Spelling > Spelling to check the entire reference.
When a misspelled word is encountered, it is highlighted in the reference and a Spelling dialog appears. You can walk through each misspelling in the reference or click the close box on the Spelling dialog to cancel the process at any time. See the Spelling dialog.
Spelling > Check Spelling to find the next misspelled word found in the reference.
When a misspelled word is encountered, it is highlighted. You can either edit it directly or Control+click on the word and use the context sensitive menu to select an alternate spelling, Ignore Spelling, or Learn Spelling.
These are other ways to start spell checking: click the Spelling toolbar button or press Control+click and select Spelling from the menu. You can also use the control keys indicated on the Edit Spelling submenu.
To spell check as you type:
Open a reference.
From the Edit menu, select Spelling, and then Check Spelling as You Type. Misspelled words will appear underlined.
You can either edit a misspelled word directly or Control+click on the word and use the context-sensitive menu to select an alternate spelling, Ignore Spelling or Learn Spelling.