About a year and a half ago, I wrote:
My conclusion is that various Microsoft updates now require 3 gigabytes of disk space.
This seems to be the case with the .NET Framework 4.5.1 KB 2858725 update, and probably more future updates. I tried installing the KB 2858725 update with slightly less than 3 gigabytes of space (and after the 3 gigabyte reserve.tmp appeared), and I was still getting error 13EC. But with slightly more than 3 gigabyte the update would install.
That is quite difficult when you run loads of VMs on SSDs: they usually don’t have an awful lot of disk space left.
The same issue holds for Microsoft .NET Framework 4.5.2 for Windows 7 x64-based Systems (KB2901983) which got released earlier this week:
The Wiert Corner - irregular stream of stuff 