What are the difficulties with the capture hypothesis of the Moon's origin?

No collision or altered trajectory

Similar percentage of oxygen isotopes

Explanation:

Capture hypothesis states that the Earth captured the moon. This is highly unlikely as such interactions of this type of bodies leads to a collision or their trajectories are altered. The percentage of the oxygen isotopes such as 16O, 17O and 18O in the Moon's basalts are almost identical with Earth. While meteorites have different percentage of oxygen isotopes.

Currently the accepted hypothesis is the giant-impact hypothesis.