Office is installing in the background (84%) stuck there.

The issue is caused because NETWORK SERVICES (NS) lacks disk read write permission. I coppied the tmp msi installer from \windows\installers and ran it and got an error code. Went to \Program files\common files\Microsoft Shared\OfficeSoftwareProtectionPlatform
and gave NS permission. The on line installer installed Office but at 94%. Expect it a similar problem.

Nope. Have tried both the 64 and 32 bit versions of the Office 2013 MSI installer, and even tried installing on a different hard drive. It installs to a certain point (84% most likely, MSI install doesn't give a percentage #), hits a problem, and uninstalls itself. Nothing works, not even a complete reinstall of Windows 8. I'm surprised Microsoft hasn't fixed this or even owned up to the problem yet. Wait, no I'm not. Their customer service is terrible.

This issue is driving me mad - has no one found a solution yet?

Also I have noticed that although the Office programs seem to work if you go into the individual programs and open files using their "Open" buttons, Office file extensions are not automatically associated with Office applications, so to double-click a Word doc or Excel spreadsheet in Windows Explorer won't launch the appropriate program.  If I try to use the default program feature in the Control Panel, it hangs on loading file types.

Hopefully they don't tell me mine is a trojan, since they uninstalled all of my anti virus and firewall software!

I can top your three times on the phone - I have had 4 calls just for this issue, and roughly 10 hours of online support time. AND for the last 2 days I have had a 09:00 call arranged to look in to this more...and both times I have not received the call!

I think I may contact customer services and complain that nobody is doing anything about this (or at least not telling us), maybe a customer services line staff will appreciate the importance of customer satisfaction a bit more than a tech support.