Defnition file not found

hello
So my defnition files used to work and now with os 2.0 they dont seem to work. was looking for what changed for the defintion files but didnt find anything. Not sure why their not working now but they do show up in the list just when i load then they say not found ? any one know why ?

Hi,
Does the file have any special character within its name? I could such a thing causing an issue