Q. Mac OS Catalina compatibility with EndNote X9

Apple have just released the new MacOS Catalina and have made the decision to drop all 32-bit application support with this release, which will impact EndNote. 

You can read more at Apple’s knowledge base article here: https://support.apple.com/en-us/HT208436 

EndNote X9 for macOS will be extensively updated for compatibility prior to the launch of Catalina. If you already have EndNote X9, please install all updates 'prior to running the new operating system'.

EndNote X8 and earlier for macOS Users Since Apple has made the decision to drop all 32-bit application support, we expect that macOS 10.15 Catalina will not run EndNote X8 and earlier.

If you have already updated to Catalina you will need to reinstall EndNote (don't forget to save a backup of your Library beforehand)

http://download.endnote.com/site/ecaeac1696b711e89ade8157bf54f977/EndNoteX9SiteInstaller.dmg

Additional important information to guide you through the steps:

https://www.crandon.com.au/endnote/faq/Catalina.html

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