pick a hole in

pick a hole in or pick holes in  {v. phr.},  {informal}

To find a mistake in or things wrong with; criticize; blame.

The witness said he had been walking in the moonlight last Sunday, but the lawyer picked a hole in what he said by proving that there was no moon and that it rained Sunday night.

Mary is always picking holes in what the other girls do.

Compare: FIND FAULT.