Can't add tracks to Traktor 2

First: Traktor 2 is extremely old. You should expect some kind of incompatibility with the modern systems.

Second: All those years i use Traktor, i never saw such an option "Drag tracks from your computer here". Where on Earth did you see that? ...maybe is on the "preparation list" which i never use since years?

Best way is to create your track collection and analyze every single track, then you are good to go, no need for drag and drops. :-)

Just navigate to your music folders (from inside Traktor!) and use the "import to collection" command. ;-)

EDIT NOTE: Drug & drop do work (first time i tried that, out of curiosity, since over a decade 😋)! However, for this to work, your music should be in a folder with read/write access (i use my D: drive). If you drag n drop from a system folder (or from a read-only folder) it won't work.