You need to go into your Garrys mod directory and delete map 67th way v4 map.
Run a search for the map name in this directory.
>>> C:\Program Files (x86)\Steam\SteamApps\common\GarrysMod\garrysmod\download\maps
The map will end with the .bsp extension (compressed format)
There will also be a .AIN extension you can delete that if you still have problems
You should also delete the GMA file just to make sure it downloads it again.
C:\Program Files (x86)\Steam\SteamApps\common\GarrysMod\garrysmod\downloads\server
(105195237)
Search for this 105195237 number and delete it only delete that number do not remove the other files.