Patch_DLC1.arch06 is missing

[OpossumPariah]

For some reason my game won't complete updating, it is stuck on an endless loop of 'Validating' and sometimes comes up saying the above file is corrupt, I've checked my game folder and the file does not even exist so for some reason steam is not downloading it. I've tried clearing download cache, changing download region, repairing the install folder and veryfing game files, none of it works. Veryfing does claim six files are missing and will be downloaded, then it just goes back to trying to validate the missing files. Anyone got any ideas?