Why are Win7/Win8.1 users not receiving Win10 pushes?

Microsoft has started pushing the Win10 installer to Win7/Win8.1 users yesterday, and some users have already completed the installation in this way. However, some user installation procedures are not very smooth. Some users who have already scheduled an upgrade have not received the push of Windows 10, so they are more confused. What is the cause? The following small series brings relevant explanations.

Why did Win7/Win8.1 users not receive Win10 push?
Cause 1: Microsoft has pushed Win10 to Windows7/Windows 8.1 users at the same time, but not in batches. So the user who hasn't received the push yet may be because you are not on the list of Microsoft's pushes. If you want to install Win10 by receiving Microsoft push, you need to wait patiently.
Cause 2: There may be a user who has not received a reminder to start upgrading Win10, and mistakenly thought that he has not received the push. Failure to receive the upgrade prompt may be because your Win10 push download has not been completed. After the download is complete, the contents of the folder “"C:$Windows.~BT” (hidden folder) will be similar to the general Win10 image root directory, and the contents of the folder that has not been downloaded will be less.