I recently stumbled upon a fix for a very annoying Evernote issue that caused no windows to display, not even the Preferences window. Hopefully, my solution below helps someone else.
After changing my password on a work laptop running Sierra, I finally rebooted after about 10 days. After a long series of prompts indicating different processes that couldn’t access the keychain, I finally gave up on fixing it and created a new login keychain. After another reboot, the prompts stopped appearing, though I had to re-enter a lot of credentials. All seemed good until I launched Evernote. The main window would not appear and all of the menu items were grayed out except for a sub-menu, but nothing was selectable from it.
After looking in the Evernote log file I found a message like the following appearing repeatedly.
"No auth in keychain. We can not login to” …
My subsequent Internet search returned people posting on Evernote forums and other places about this problem, along with the above error message, but no solution. When I looked in Keychain Access, I found that there was no longer an entry for Evernote. Thinking more about it gave me the idea that Evernote might have a bug that put it in a state in which it couldn’t find the keychain entry, but wouldn’t prompt me to provide credentials to add a new entry.
While trying to fix the problem I repeatedly killed Evernote and EvernoteHelper. That led me to poke around with EvernoteHelper in the OS X menu bar. I clicked on the display monitor icon to save a screenshot to Evernote. This brought up an Evernote login dialog. After I logged in, the main window in Evernote suddenly appeared and a new entry for Evernote appeared in Keychain Access. Problem solved.