Can only view Mail in full-screen mode

I've just gotten off the phone with Apple Support who solved this problem. Open mail. Go to Mail Preferences/Viewing and Check box "Use classic view". Then open a new mail viewer window (File/New Viewer Window). At this point, assuming you have the same problem that I did where you can only see the window showing emails, but not the email preview window, move your cursor so it hovers right at the bottom edge of the window. The cursor will change to a horizontal bar and an up arrow. Click and drag up a few inches. At this point you should now be able to see the email preview window. Now go back to Mail preferences and uncheck classic view. The window now stays open in non-classic view. Hope this works for you too.

1. From the application's menu bar, select

Window ▹ Zoom

2. If an external display is connected and turned off, either turn it on or disconnect it.

3. Open Mission Control. Close all desktops except Desktop 1 by positioning the cursor over each one and then clicking the X button in the top left corner. In Desktop 1, move the missing window, if need be, so that it won't be hidden behind the Dock.

I am having the exact same problem. I've repaired disk permissions, gone into safe mode and repaired permissions, reinstalled Yosemite and even deleted the saved mail application state but nothing is fixing this. In addition to junk mail no longer being filtered, I'm ready to go back to Mavericks.

Thanks BRegan6 - this has been driving me nuts all weekend. I just made the jump from Outlook to Apple Mail 2 weeks ago, and this just about pushed me back to Outlook. How has this bug NOT been patched already? Craziest thing to not be able to bring up a Mail window...especially since that is the most-used app for most of us.

Fixed me too! This has been driving me crazy for three weeks! Even the Geniuses at my Apple Store couldn't figure it out. I did an E&I, but as soon as I synched with my Time Capsule the issue was back. I wish I had some idea why the issue started in the first place... I want to make sure I don't do whatever I did again (plus maybe that'd help them fix the bug). But at least I know how to fix it now. Thanks BReagan6!

If I exit fullscreen mode, Mail crashes.

Do you get an alert that it has "quit unexpectedly?"

Please post the rest of the crash report.

Thanks so much for posting. I have tried numerous options in various discussion groups, but only your suggested approach worked for me.

So wait, what is the official fix? I am trying everything. Apple support was no help.