How old is your map? I don't think that minecraft 1.10 is designed to properly handle worlds created in alpha/beta, since the save file format and generator have been changed several times.
Listen to the guys above, create a new world and copy everything over before the old map gets completely messed up. If MCedit doesn't work for you, you can try to get the spigot server and install Multiverse-Core and WorldEdit plugins, then just tp between worlds and move your stuff.
