Library guides: EndNote: Upgrading from earlier versions of EndNote

If you are new to EndNote and have no existing EndNote library, feel free to start with EndNote 21 but be aware of backward compatibility issues if sharing a library with others who are using EndNote v.9.2 or older. Read more about backing up your library and any customized content files (e.g. output styles, connection files, and import filters).
Only one version of the EndNote desktop application can be installed on your computer.
Ensure that you backup your existing EndNote library first or make sure it is synchronised to your EndNote online account (if using EndNote Online)
Before upgrading from EndNote X9.2 or older, ensure that your EndNote X9 is updated right up to the latest version of X9 (X9.3 or above). This will convert your library to a format that will be compatible with EndNote 20/21. However, it will also convert your library to a version that will not be backward compatible with vX9.2 or earlier. This process cannot be reversed. Read more about Library Conversion and Backward Compatibility here.

From late 2019, EndNote for Mac changed to a 64 bit program and Apple no longer supported 32 bit software. EndNote libraries created in Mac version X9.3.2 and above are no longer compatible with earlier Mac versions or Word versions X9.3.2 or earlier.
If you upgraded to EndNote Mac version X9.3.2 or above you can only open libraries in this version or above.
If you are using Catalina OS or above, you must upgrade to EndNote 20.
You can open libraries created in older versions in the newest version - they will be converted to the newest format. The libraries will no longer open in earlier versions and this process cannot be reversed.
Unsure of the latest macOS version? Check here.
Always create backups of your libraries before upgrading.

Note: If you are still using a Mac with the Apple M1 chip please see the following article EndNote: Apple M1 chip compatibility

Check compatibility and system requirements here.