Currently whenever I try to update WoW, WoWTLK or WoW Live, they freeze on their Initializing message.
In my Task Manager Battle.net and Battle.net Update Agent are using 0.0MB/s
I have thus far tried restarting, holding shift while shutting off to avoid hibernation, deleting the Cache, uninstalling and re installing Battle.net.
What else can I do?
Are you using security software? These often block updates.
I know of a fix but you’ll have to bare with me on this one…
Halt any updating or patching that Battle.net is doing. The blue button should be clickable and say either “Play”, or “Update”
Close down Battle.net completely. It will be quite difficult due to the spaghetti and bloatware the “smart developers” have managed to get in there. If you’re unsure then I recommend re-booting pc
Navigate to the root directory of your Battle.net client, you know you’re in the right spot when you see the .exe named “Battle.net Launcher.exe”
Here, delete any folder with a [dot] in front of it. If I had to guess I’d say these are most likely temporary folders. Battle.net won’t give 2 flying ducks and just fetch new ones so please don’t excrement your pants. Yet
Repeat steps 3 and 4 but this time navigate to the game you are having issues with and wipe your cheeks with folders, here, also starting with a [dot]
Once you’re done with that, close down the file explorer, start Battle.net, and lower your expectations because you’re not done yet. 
Select the game in question and inspect the big blue button, the same one from before. Sorry, you had to find out like this but the big blue button is actually two buttons. There is another one conjoined with it, this one has a cog. Click it
Choose “Scan and Repair”
This process is slow, even the initializing part before it gives you a percentage is slow. This is due to all the complicated calculations the client has to make in order to best serve you an ad for the newest retail mount. Don’t worry though, we’re not sitting through the entire thing
Since we’re only doing this to get Battle.net to stop crapping itself you only need to get it to 2%. Once you got 2% you can press the cross to stop it
Done! This vodoo ritual of a troubleshoot is what gets my game and updates back in working order. If it’s still not bueno for you then now is when I’d recommend going through with the pants-filling mentioned earlier. Good luck!
Nope, the only thing I have going on is Windows Defender, which isn’t set to any “strict” mode or anything of the sort