to make it start windowed
find your EP9 exe (in The Sims 2 Ultimate Collection/Fun With Pets/SP9/TSBin, wherever you have your origin games saved)
make a shortcut on desktop
right click the shortcut->properties
find where it says target and add to the end of the link a space, followed by '-w' (no quotation marks)
it should look like this: "[Wherever It Is On Your Computer]\The Sims 2 Ultimate Collection\Fun with Pets\SP9\TSBin\Sims2EP9.exe" -w
then use the shortcut and it should start windowed.
It worked for me so I hope it would work for everyone else having this problem
I tried and it still gives me the same message.
