OK - after browsing around I found that the problem appears to be associated with the bootloader. My system is dual boot. I have Windows on one SSD with its original bootloader. Another SSD holds Ubuntu 14.10 with a GRUB bootloader - this is set to boot first in the BIOS. My files are on a separate HDD.
Here's what worked for me.
- Set the Windows drive to be the boot drive in the BIOS.
- Reboot into Windows (i.e., avoiding GRUB).
- Run Microsoft Update again and allow the install to complete along with restart. It did so without any issues.
- Restart computer and reset BIOS to place the Ubuntu SSD first in the boot order.
- All working normally and confirmed that KB3033929 has been installed.
Not sure why the bootloader should be a problem. I have another machine that runs Windows 7 Home and Ubuntu on a partitioned drive - GRUB is the bootloader and yet there were no issues with the update. Could it be that the 64 bit update is the problem??