Just so we're clear on this, I'm talking about mandatory data install that some games want before you can actually play them (eg F1 2010, MGS4) not the actual game folder itself (since everyone knows where that goes )
I'm having problems getting F1 2010 to load beyond the initial "Loading" with spinning logo screen and deleting the game install data via the XMB has fixed it. Today I done the same thing and it didn't work. I even deleted the game totally from my internal drive and tried again from scratch but that didn't fix it either.
That's why I want to know which folder the game install data is in so I can go in via FTP and make sure the install data has been deleted properly.