My .minecraft folder does not have the folder resourcepacks, and I can't rename it.
I have library open in finder and the application support folder with Minecraft open, but I don't have resource packs, and it cant be renamed to .minecraft-old.
First of all, on a mac the folder is not .minecraft, and you are not allowed to name a folder with a name starting with a "." so change it to "minecraft-old". When you launch minecraft, it will generate the folders for you, if not, manually create the resourcepack folder and minecraft will load it (as long as the version uses resource packs, not texture packs).
First, it's not called "resource packs" but yes "resourcepacks". Second, in a mac it's not called .minecraft. I don't have a mac, so I don't know what the name is. But if you want to install a texture pack, go to "Options" (or settings, depending on the language) and click "Resource Packs". Then, click "Open resource packs folder". It will open the resource packs folder.
Installation
Place your resource pack there (zipped or unzipped). Go back to minecraft, close the Resource Pack chooser and open it again so that it can reload. Then, click the little arrow that appears when you hover the texture pack name and it will be selected. Click "Done" (or "Ok" depending on the language), wait about 10 seconds and your texture pack will be loaded. (I don't know why I made a complete guide of how to install a texture pack, but it can be helpful)
