Q: Updating my Mac to 10.10.4

I had the same problem and many others have already reported it too. For me, downloading and installing the Combo Update did the trick: OS X Yosemite 10.10.4 Combo Update

Same problem here.

Any help? Restart doesn't help.

Same thing here. I'm downloading the update combo to give it a try.

What's the difference between the combo vs non-combo?

The delta update can only update 10.10.3 to 10.10.4. The combo update can update any version of Yosemite 10.10 to 10.10.4. That could repair issues with 10.10.3 that the delta can't.

Mac mini, OS X Yosemite 10.10.3; Apple Watch, 38 mm silver AL, Watch OS 1.0.1; iPad Air 2 & iPhone 6+, iOS 8.3

I have managed to solve the problem in the following way

1. starting the Mac in safe mode

Follow these steps to start up into safe mode.

• Start or restart your Mac.
• Immediately after you hear the startup sound, press and hold the Shift key.
• Release the Shift key when you see the Apple logo appear on the screen

2. Once the computer started to re-start in normal mode

3. once re-started in normal mode to go to application store and click in the update of the version 10.10.4. It downloaded and restarted and installed the update automatically and without any problem. Now the Mac is in the right version of Yosemite as you can see.

Hope it helps!

I downloaded combo and installed...... Fixed it!

Thanks for the post.  This worked for me also.

The combo update worked fine.