Microsoft has begun downloading the Windows 10 upgrade to some PCs whose owners had previously "reserved" a copy, hinting that those customers will be among the first to see the upgrade notice on their Windows 7 and 8.1 devices.
"'$Windows.~BT' has been downloaded to the C: drive of the laptop I am using to write this message," said someone identified as John Andrew Davis in a message on a Microsoft support forum late yesterday.
Other reports, including several on Italian websites early today, also said that the download had landed on PCs.
"Several users have noticed a new folder in the main memory of your PC called '$Windows.~ BT' that contains the files for the installation of Windows 10," said Plaffo.com.
"That folder is located in C:\ and is visible only if you enable the display of hidden files and folders in Windows," added Windowsteca.net.
Both sites posted screenshots of the downloaded files showing within the Explorer file manager.
Microsoft has made several moves to try to alleviate Internet congestion as it serves up the free upgrade, including staggering the distribution in waves and pre-loading the upgrade to customers' devices.
Users who asked for the upgrade through the "nag-and-notification" app that Microsoft planted on Windows 7 and 8.1 systems last month implicitly agreed that Microsoft could download the necessary installation file(s) to their local storage without additional warning. Only after the download is completed and Microsoft has checked the device for compatibility problems will the app tell the user the upgrade is ready to process.
Those notifications may begin as early as tomorrow for the general population: Microsoft has, however, promised its Insider program testers the first crack at the upgrade.
Yesterday, Dan Rayburn, an analyst at Frost & Sullivan, citing ISP and CDN (content delivery network) sources, said that Microsoft would begin downloading bits to some users' devices starting at 4 p.m. ET. Microsoft had wanted to begin on Saturday, July 25, but had to postpone as its delivery and distribution partners freed up capacity for the massive 40Tbps (terabits per second) the Redmond, Wash. company had reserved.
From the reports, Rayburn was correct.
Although pre-loading is supposed to take place while the PC is not being used or worked hard, some users may notice symptoms ranging from a slow-down in accessing the Web through their browsers to stuttering video or audio streams as their usable bandwidth shrinks. The download will resume at its previous mark if the connection is lost or interrupted by a system power-down.