Troublesome possession (5,8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
white elephant
(Other definitions for white elephant that I've seen before include "The inapt wheel (anag) - extravagant item that proves useless" , "Unwanted gift" , "Opening player" , "Expensive, unwanted item" , "Troublesome or useless possession" .)