Yeah, Office 2010 is old, but it has been getting updates, so the security issues are probably the same, or similar.
Windows Defender could still be blocking some of your actions. Unless you have it set to Verbose, or not on Silent, or whatever the setting is, it can block actions silently.
Norton is probably just turning on and off scripting in the Registry for PowerPoint when I make those changes in the Norton interface.
As above, I was just using a Hyperlink to a Shortcut that only had the
MC26.exe /Replace TREEPATH=Playlists\WhitePlaylist command, and the Mini View came to the top and playback started. It is very strange that we are getting different results with that... Ah, open MC in Mini View, right-click in a blank area of the interface, then select View > Always on top. Test again, just with a Hyperlink to a shortcut, and no
MC26.exe /Mode Mini command. Oh wait, you said you were already using "Always on top". Hmmm.
If playback still doesn't start, you could try turning on "Options > General > Behaviour > Start playing when files added to Playing Now". As the
MC26.exe /Replace TREEPATH=Playlists\WhitePlaylist command adds files to Playing Now, that should force playback to start. But I don't need to have that setting on for this to work.
The only other setting that I can think of which might affect the Mini View coming to top again using the Hyperlink is the "Options > General > Interface > Minimise to System Tray", which I have turned on. If you are minimising to the Taskbar that may give a different result. However, when I turned that off my link still worked.
If I use /Replace instead of /PlayReplace in my second request to play a playlist, MC just stops the current playlist and fails to start the new one.
Does it change the Playlist? I was testing with just one Playlist, but changed to using two separate Playlists to confirm that
/Replace was actually changing the Playlist using my Hyperlink. Indeed it was, and the second Playlist was being played correctly, from the beginning. Note that I do still get the Powerpoint warning message about opening the file, as I haven't turned off the security settings required, and I am showing the slideshow in Protected Mode. But I think you have that covered in your installation.
Note also that if MC isn't running when I click the second image to open the Hyperlink, MC is opened in full Standard View, the Playlist is loaded, and the Playlist is played.