Things I have tried;
1/Reinstalling 4 times
2/Verify integrity of game cache (comes up with '1 FILES FAILED TO VALIDATE AND WILL BE REACQUIRED' downloads a small file but does not fix the issue) I re-validate and it still shows up with 1 files missing.
3/checked files with a friend. ADDONS folder is missing around 200mb all together. E.g. a3.pbo is 3000kb when my friends is 4000kb. This happens with multiple files.
I have tried to copy my friends addons folder over, however when i do it, steam deletes them and re downloads it again.