For when a simple repair just doesn't do the trick.
1. Navigate to your WildStar folder, which by default is located in C:\Program Files(x86)\NCSOFT
2. Right-click on the "WildStar " folder and select "Cut."
3. Make a new folder on your C: drive (or whichever drive you want WildStar running from) and name is "Games." For example, C:\Games.
4. Once created, open this folder and "Right-click" the white background, selecting "Paste." This should move your WildStar folder to this new location.
5. Once the move has completed, open "Control Panel's Add/Remove or Programs depending on your OS version and uninstall any instances of WildStar.
6. Once uninstalled, download a clean copy of the WildStar launcher using this link: http://wildstar.patcher.ncsoft.com/Wildstar.exe and move that file to your Desktop.
7. Right-click this file and select "Run as Administrator."
8. Once running, install Wildstar to the same location you just moved it to. For example, if you picked C:\Games\WildStar, then you would "Install" WildStar to C:\Games. (Note, you would NOT install to C:\Games\WildStar as that would install it into C:\Games\WildStar\WildStar"
9. Once "installed" allow the launcher to update and it should pick up the files that already exists and patch to current, instead of doing a full re-install.