I didn't know 10049 downloaded by itself. My PC just suddenly restarted. When I saw the circular progress bar after the restart. I forced shut it down. I needed to disconnect my 3 other SSDs first. Then it reverted back to 10041.
I'm updating to 10049 from 10041,, on the screen that says "Keep your PC on until this is done. Installing update 1 of 12...." Question,,how long does this part take,,,been 45 mins so far.
Source: Windows 10 Technical Preview Build 10052 now available for phones
See also: http://windows.microsoft.com/en-us/windows/preview-faq-right-for-me-phone?ocid=tp2_site_faq_down
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Source: Windows 10 Technical Preview Build 10041 now available
Windows 10 build 10041 ISO files available for download.
https://www.tenforums.com/windows-10-news/1946-download-windows-10-technical-preview.html