Windows couldn't finish installing updates, 0x80004005 Error

I've been trying to install the anniversary update but it keeps failing. When I attempt through "Check for updates" in settings it finishes downloading/installing then restarts my PC, when it turns back on I get the notification that updates couldn't finish installing. I have tried the Win10 upgrade assistant from Microsoft but it either gives me "Something went wrong 0x80004005 Error Code" or it will continue to download/install and open a window with the dark blue background but then exit and say in a small pop up "Windows 10 update failed."
Any solutions for my problem?

I had the 0x80004005 on many occasions, at the first restart during the update. I tried updating with both the Windows Update Assistant and a DVD created using the Media Creation Tool but always with the same failure.

Eventually I tried a vanilla install on a spare hard drive. Not surprisingly this worked. I noticed that during this install Windows also created a System partition. I had no systems partition on my main hard drive and this has never caused me any problems. On a hunch I copied my old version of Win 10 to the spare disk, leaving the systems partition in place. This time the upgrade worked! After upgrading, I copied the upgraded version back to the disk without the systems partition and it still seems fine.

So at least in my case, it seems the system partition needs to be there during the upgrade process but not subsequently. This ties in with the fact that I had absolutely no problem upgrading my sister's PC which did have a system partition.

I've had luck doing a clean boot then upgrading on several occasions...

https://support.microsoft.com/en-us/kb/929135

you're basically shutting off all startup items in msconfig, disconnecting all usb and internet cables, and restart, then upgrade...