Without Bigfile.000 , the executable ( tombraiderlegend.exe ) has nothing to load. The game cannot start. It is the heart of the installation.
If you are using the "Next Gen Content" mode, you also need the companion files. Missing Bigfile.ngc will cause graphics glitches. Download Bigfile.000 For Tomb Raider Legend
: Sometimes security software blocks the game from reading these large archives. Adding an exception for the game folder in your antivirus settings can resolve "failed to open bigfile" errors. Without Bigfile