A technical preview is NOT meant for everyone, a many things have bleeding edges, many of favorite programs may not work, so such releases are meant for brave hearts, who want to jump in savor the raw taste of painfully ripening fruit.
Well, less said, if you are one of them and came to a situation like all of a sudden your Windows 10 preview build stops downloading updates, however, showing “downloading 0%” you may try the following
Open Windows services (run -> services.msc)
Stop the Windows Update Service (You have to try couple of times to stop it successfully)
Using explorer or run command %windir% to access “Windows” folder
Locate “SoftwareDistribution” folder
Open the folder and delete all the content (Please note, this will possibility remove all the log entries for previously installed updates). Administrator privileges will be required for completing this act
Once the files are deleted, restart the windows update service.
Return to Windows update page, retry the update
That should fix the annoyance until next occurrence!