I cannot upgrade my Windows 10 tech preview from build 9879 to build 9926. Can anybody help?

[Windows Central Question]

i cannot upgrade my windows 10 tech preview from build 9879 to build 9926. can anybody help?

i tried installing some three to four times using the windows update and a couple of times using the iso I downloaded. everytime the install went on for a long time, some 90% or so. but then the screen flashed and I got an message.. "restoring your previous windows version".