4.2.1 update won't update

Hi,

I am trying to update my site to the 4.2.1 and I keep getting the same problem. I click on update and it gets to here:
Downloading update from https://downloads.wordpress.org/release/wordpress-4.2.1-no-content.zip…
Unpacking the update…
Verifying the unpacked files…
Preparing to install the latest version…
Enabling Maintenance mode…
Copying the required files…

and then it stops. I have to remove the maintenance file to get back into it. I have removed the uploaded 4.2.1 files in the update folder and I try again and it does the same. Even if I don’t remove the 4.2.1 files in the update folder it gets to the same point and stops.

Is there anything I can do?