Up until 2 hours a go in Endnote X6, when I clicked on sorting by author or any other field at the top of my reference library, it would sort my reference accordingly. Right now (no settings changed), when I click author it sorts strangely. I could not also sort it out by year or any other field. Please noted I tried to use Tools->Sort Library, but nothing changed. For example, a manual sorting of “Tools>Sort>First Author” did result in the same unusual sorting.
Did you try setting the Sort Options to: Author, Year, followed by whatever additional specified fields? (Note that the 1st setting is for Author and not “First Author”.)
Can you provide a screenshot of the Sort Options dialog box? Also, are you storing the author names in the reference type Author field in: 1) 1st name then last name order; or 2) last name then 1st name order?
This sounds weird – you are talking about your clicking on the top bar, right? – and I assume you tried rebooting the computer? – you might try backing up the .enl and .DATA folder and then try recovering your library.
if those don’t work, I would not hesitate in calling tech support!