I'm getting the notice 'Please install KB2999226 on your machine before initiating installation' when trying to install Update 5.
What is KB2999226?
In regards to Andrea's post for different KB downloads for Windows versions. I too had someone receiving this same error message during Install. You also need to look for the KB download for 64bit or 32bit OS whichever matches your system. My user downloaded the 32bit which was not working till they downloaded the 64bit version.
I have had another user having this same issue regarding the KB message. They too were trying to install the Windows 7 32 bit version on a 64 bit system. They were unable to install download and have MS install. They were not finding the 64 bit version.
Answer Verified By: Johannes Lerch