EndNote X1 Libraries operate on a unicode platform which allows for advances such as unlimited references in each library and the use of non-English characters. The drawback is that EndNote X1 can only read versions back to EndNote 8. It will not read older pre 8 versions unless you convert the new library into EndNote X1. Please keep this in mind when you upgrade or share a library.
Upgrading/Converting old EndNote Libraries
EndNote 8, 9, X and X1 can automatically convert libraries created with earlier versions of EndNote (versions 5, 6, or 7) to the version 8, 9, X or X1 format. To open or convert an older EndNote library:
The following are some pointers for getting started: