I can't install Yosemite 10.10.1...

There is no beta version of 10.10.1. I suggest:

Reinstalling OS X Without Erasing the Drive

Boot to the Recovery HD: Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.

Repair the Hard Drive and Permissions: Upon startup select Disk Utility from the main menu. Repair the Hard Drive and Permissions as follows.

When the recovery menu appears select Disk Utility. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the main menu.

Reinstall OS X: Select Reinstall OS X and click on the Continue button.

Note: You will need an active Internet connection. I suggest using Ethernet if possible because it is three times faster than wireless.

Re-download and install OS X Yosemite 10.10.1 Update.

Also see:

Reinstall OS X Without Erasing the Drive

OS X Yosemite- Reinstall OS X

Note: You will need an active Internet connection. I suggest using Ethernet

if possible because it is three times faster than wireless.

Build 14A839 is the original 10.0 official release of OS X on Oct 16th, 2014. The 10.10.1 OS X release is Build 14B25.

Not sure what you mean by the "beta version" - there is another 10.10.2 developer release I think (build 14C68k I think), but you need to be an official Apple developer to get a copy of that.

So were you able to download the 10.10.1 OS X updater? Did you get it from the App Store or from downloading from Apple web site at OS X Yosemite 10.10.1 Update. You might try to download again in case the file got corrupted in some way during the download process and then try and install it.

Also look at the file /var/log/install.log and see what it says about the upgrade process - my guess is there was some sort of error it could not handle and had to give up. Do you have plenty of free space on your boot volume? Is there anything unusual about the configuration of your iMac (external disks, etc)?

If you need more instructions on how to see what's in the install.log file, then ask.

Good luck...

So when you download the 10.10.1 update from the Apple website does it download OK (should have a file called OSXUpd10.10.1.dmg that is 311.8MB in size). So you double click this "dmg" file and it will mount a volume called "/Volumes/OS X 10.10.1 Update", and on that volume there is a file called OSXUpd10.10.1.pkg and if you double-click that, it starts a program called "Install OS X Update". Then you have to answer a couple of questions and then it should do the update and then ask you if it's OK to reboot the computer.

Which parts of this sequence have you been able to do and which parts of it have you not been able to do?

hello, still its the same problem with the other. I followed your steps upon installing the update still it says that OS X Update is not verified; i tried the automatic update which you can directly find it in the app store and the manual which can be downloaded from the apple website for how many days hoping for a success but it didn't run well. any suggestion posted will be appreciated.

Macbook Pro (early, 2011)

What was the exact error message you got? If it was "The update could not be verified. It may have been corrupted during downloading. The update will be downloaded and checked again the next time that Software Update runs." then just try the manual download again - it's big so will take a while unless you have a pretty fast internet connection to your ISP. It's over 300MB - so give it plenty of time. If it fails with this same message, try a couple more times. If it still fails you might call and ask your ISP if they can do anything to make this download work to completion without errors.

Hang in there and I'm betting it will download fine....

What I get happening is that the app store says that there's an OS update, so it downloaded it and when I restart the iMac, it starts the installation process, but that's as far as I get. The progress bar stops all movement and says that there's 4 minutes remaining, but let it sit for 10+ hours! And it never moved. The only way that I can get rid of it is to hard boot the iMac and then when it's all rebooted, it says that it was shut down due to some error, but won't let me report it to Apple.

Suggest starting a new thread for your problem so more people will see it and offer suggestions

I can download Yosemite, but I can't install it to my hard drive because it says Time Machine uses it. How do I get around this? I keep a bootable copy on a separate hard drive.

Can't Install OS on Volume Used by Time Machine