If you have a full joints skeleton in Maya then you deleted the left side of the am joints – for example – now you want to mirror the right side to the left side, if you do it with the traditional way, Maya will simply crash down.
So How can you do it ?? simple watch my video

if you have any questions, problems, feedback Please

i did the modeling, Rigging & Animation Walk Cycle in 5 hours using maya
i hope you like it…. your feedbacks are welcome.