I spent almost my whole day on this. I use Evernote quite a lot, so I need it. I upgraded to High Sierra last night, and this morning discovered I could open Evernote, but it had no functionality. I contacted Apple support, who told me that Evernote is not compatible with High Sierra. They had me erase my entire hard drive and return to Sierra operating system. Fortunately I had done a recent backup, but it was a terrible process. I warned the other Mac users on my team that shares Evernote with me not to do the upgrade. Will Evernote notify us when it is compatible with Mac's new High Sierra, so that we can do the rest of the upgrade?