Sorry for the double post... but should all those 150 GB be on the SSD?
I know it is a stupid question but...
That 150 GB should all be in the same volume of the same drive--ideally your SSD.
Well that creates a number of challenges as yes, I have an SSD but I do not have 150 GB on my SSD at the moment. I might need to relocate files.
I did not have this problem with EA as it was in my /D disk .
If the game runs now from your D:\ drive you can always make sure you have 150 GB free on that drive to run the upgrade and then set up a Steam Library on your SSD and move the game over if it turns out you do have the space available. I have a bunch of drives on this system and am always moving games around.
Or I might just run it on my D disc (plenty of space there). EA ran very smoothly. My video card is a bit under the minimum requirements but the rest of the system (like 16 Mb of RAM) is at or not far from the recommended requirements (definitely above the minimum). Otherwise, that means I will have like 2/3 of my SSD filled only with BG3
If it does not work, then I will think.
I can't remember if I can add memory to the SSD of my laptop (yes, I am gaming on a laptop as I like to have it all on one computer).