Windows – cmd msg command won’t send to other computers

Try this on the Windows 7 machine:

1. Open Administrative Tools -> Local Security Policy.
2. Click on Local Policies -> User Rights Assignment on the left.
3. Double-click "Deny access to this computer from network".
4. Select Guest and click Remove.
5. click OK.
6. EDIT: Ensure in the Permissions for the network share, that Guest is included, since it's no longer part of the Everyone group.
7. Use regedit to go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System and create or modify the value of LocalAccountTokenFilterPolicy (32-bit dword) to 1, so the remote logon token will not be filtered (see here).

The reason has to do with the architecture of Microsoft Windows networking. In your setup, Windows uses a rather mundane way of enumerating network devices: Broadcasting. Virtually, it broadcasts a message on the network asking any device that can hear it to report in.

Of course, you probably expect a fast response, so net view waits a split second before listing every device that has reported in. The Network view, however has the luxury of waiting as long as you keep it open and updating its device list in real time. Hence, if it takes longer for a couple of devices to report in than the amount net view waits, you get a partial list. But Network can still list devices even if they report in late. They appear late, but if that latency is just a split second, you don't feel it.

It is of course possible for some computers to become stealthy by actively refusing to respond to the device discovery broadcast message. That's what a firewall can do.