humm...weird...and you don't get the password prompt upon logon? You favorite don't get mounted or they get mounted by VeraCrypt exits afterwards?
This is the simplest configuration and it works for me and others on Windows 10. This is the basic test that we all do to check if VeraCrypt works (favorite mounting, both normal and system).
Thus, there must be another cause. First thing is to check Windows Events Viewer to see if there is any error (both on System and Application) that would explain this.
Second, try running the same the command line from a command prompt and check if you get the password prompt: "C:\Program Files\VeraCrypt\VeraCrypt.exe\" /q preferences /a logon /a favorites
Third thing, verify if you have any software on your machine that can block VeraCrypt from auto-running at startup: some security software offer such functionality and they may falsely target VeraCrypt binaries.
Anyway, I have done a test on a Windows 10 Pro with an encrypted USB key that uses only a keyfile (no password). I recorded a video that demonstrates how to set this encrypted USB key to mount automatically at startup without typing any password. Here is the link to the video: https://www.youtube.com/watch?v=gbJKUEUXWVo
As you can see, it works as expected. That's why I said there is something else involved in your case.
This is the simplest configuration and it works for me and others on Windows 10. This is the basic test that we all do to check if VeraCrypt works (favorite mounting, both normal and system).
Thus, there must be another cause. First thing is to check Windows Events Viewer to see if there is any error (both on System and Application) that would explain this.
Second, try running the same the command line from a command prompt and check if you get the password prompt: "C:\Program Files\VeraCrypt\VeraCrypt.exe\" /q preferences /a logon /a favorites
Third thing, verify if you have any software on your machine that can block VeraCrypt from auto-running at startup: some security software offer such functionality and they may falsely target VeraCrypt binaries.
Anyway, I have done a test on a Windows 10 Pro with an encrypted USB key that uses only a keyfile (no password). I recorded a video that demonstrates how to set this encrypted USB key to mount automatically at startup without typing any password. Here is the link to the video: https://www.youtube.com/watch?v=gbJKUEUXWVo
As you can see, it works as expected. That's why I said there is something else involved in your case.