Glad it works for you. I have been using this for several years and it does work great. Wish I could take the credit for it, but I got this from this forum many moons ago. ( I think it was from an adesk person)
To get rid of the warning message, can you not disable the message by selecting the "Never show this thing again" button. It is behind the promt button on the warning message. They added this sometime ago just to warn people if they have overblotted VBA code in the idw. I think there is a performance issue when you open several idws in the same session. I can have several idws open at the same time and I don't have an issue. But if I tried to open say 100 idws in the same session, it might get bogged down.
If you don't need the variable, just remove it from the code. If it was me, I would just leave it there, never know if you will need it later. I don't know what the difference is in file size with and without the systime written to the custom prop. I am sure it is a very small difference.
Thanks karthur for sharing that code.. it's perfect !!!