Can't mirror objects!!

Help! I’ve been working on a model for about a week now. I could run the mirror modifier all week long just fine. Now I finish my project (a shoe) and I want to mirror it to the other foot in real-time. However, I’ve discovered a rather large issue: I can’t mirror objects! I can use the modifier just fine and then make it real but I need to be able to mirror other parts of the mesh down the road. Is there something that I have switched off that is causing this?

Mind you, I have had this same problem before. I’m tired of running into this so I’m wondering what it is doing? I did delete a few bones so I’m wondering if there is an issue there? Basically trying to mirror the object does absolutely nothing. I’ve tried switching between local and global mode… moving the object centers around… everything I can think of.

if you are using 2.46, select the bits you need to mirror in edit mode, then hit M then X ( or Y or Z depending ) you have to hit both m AND x for anything to happen.

Mirror also works in Object mode:
Press ctrl+M

Another trick to mirror is:
select the object(object mode) or the part you want to mirror in edit mode and simply duplicate it, and then scale it to a negative value, as soon as you move over 0 the mesh flips. works great for bones.

I read you deleted some bones… is your mesh skinned and armatured?
Then mirroring isn´t working prolly because you try to mirror the mesh without bones. So the vertices are still withted for instance to the left side bone, while you try to make a rightside copy of the mesh without an rightside bone.