Mac users - have you downloaded OS X Yosemite? How's it working for you?

[OakLeaf]

Which app(s) have the question mark(s) in the Dock? Are you sure you have the latest version of each of those apps installed ... and that you had the latest version BEFORE the OS upgrade?

Can you launch the apps by clicking on them directly in your Applications folder? If that's the case, then the simplest thing will be to drag the old placeholder question mark out of the Dock and drag the current, working one in. You can either drag it directly from the Applications folder (it won't move the actual path to the app, just create a path from the Dock), or else when the app is running, click and hold its icon in the Dock until a pop-up menu comes up above it (again, something that as far as I can tell you have to physically click the button), then from the Options submenu, check "Keep in Dock." Then you can drag the icon to wherever you want it in the Dock.

If you can't launch the apps from their icons in your Applications folder, if you restored from a backup, it's possible that you excluded your apps from the backup protocol when you set it up, so you will have to download and re-install fresh copies. That's really best practice anyway.

What browser are you using?

[IBrakeforPastry]

The question mark is standing all by itself. When I hover the cursor over it, a bubble shows above it saying "install OS X Yosemite". Does that mean it's not completely installed? Nothing happens when I click on the question mark. If I right click, I get the option of removing it from the dock. I think I'll do that. Just make it disappear.

I'm using Safari.

[OakLeaf]

Ah ... The way I understand it, once the installer has run, it deletes itself from the hard drive. Sounds like the cleanup routine didn't finish somehow. Yeah, I would just delete that if it were me. If you still have the disk image on your hard drive, copy that to an external drive just in case you need it in the future. But if you don't, there's no reason to save the icon.

But I thought you were saying the icons for the other apps were also appearing as question marks?

[IBrakeforPastry]

But I thought you were saying the icons for the other apps were also appearing as question marks?

No, the apps are fine. There was a question mark over iPhoto, but that went away after a re-start (after the update).
My two biggest problems now are the cursor and the freezing. It seems to work fine on this message board, but on another one that I've been visiting often, it freezes, or doesn't download the page completely.
Oak, I really appreciate your help, but I don't want you to waste your time on my problems. If you do think of something, though, I'll be here. Thanks!

[OakLeaf]

You're not wasting my time, you're giving me incentive to work harder on figuring it out for myself!

Okay, I finally imported my mailboxes, and here's what I was able to do.

Supposedly you should be able to drag the message pane closed (using the sizing bar in the top bar), but I wasn't able to do that. It would only go so narrow and then stopped. But when I switched to Classic layout (Mail>Preferences>Viewing), which has the message pane on the bottom rather than on the right, I was able to drag it completely closed (which now IIRC is the same thing I had to do when I originally set it up in Snow Leopard, it's just been so long I'd forgotten). Then once it's completely closed, it stays closed even if I switch the view back to modern layout (or whatever they call it if I un-check Classic).

With all Apple's vaunted security, it's kinda dumb to not only let it open messages by default, but make it so convoluted to turn that off ...