I've normally have found success without having to go as far some of the above suggestions, even if they are salient.
What I recommend you try first is to switch from metric to SAE or vice versa. More often than not, you can go up a tad in size for the wrench, and get enough of a grip on the bolt to remove it.
What I recommend you try first is to switch from metric to SAE or vice versa. More often than not, you can go up a tad in size for the wrench, and get enough of a grip on the bolt to remove it.