EndNote X8 "Cite As You Write" is NOT compatable with IOS Yosemite. To use EndNote X8 you must upgrade to El Capitan. Contact OIT for assistance.
EndNote X7 users may experience issues after upgrading to Mac OS Sierra
Known problems include loss of the pdf viewer / annotator and problems downloading plug-ins from some third-party websites
OIT recommends not upgrading to Sierra at this time
If you have upgraded and would like to revert to El Capitan, contact OIT to re-image your Mac
Note: Windows is shown here, but the same rules apply for Mac OS