Help!!!! [UnrealLightMass.exe - Bad Image]

Hi, I have just recently downloaded Unreal Engine 4.8 and I have been having some trouble. Whenever I make any changes to a level, it tells me I have to rebuild the lighting when I press play. I went to build, and clicked lighting only. This attempted to download something, and I allowed it. It then proceeded to build my lighting, and completed. However, when I clicked play again, it still said I had to rebuild my lighting. I then tried to rebuild the whole thing by just clicking build. At first this seemed fine, but then I got a windows popup:

"UnrealLightMass.exe - Bad Image

C:/Users/Me/AppData/Local/UnrealEngine/4.8/Saved/Swarm/SwarmCache/Jobs/Job-5510664B-49925595-ADF5AE83-66A81E19/UnrealLightmass-Json.dll is either not designed to run on windows or it contains an error. Try installing the program again or contact your system administrator or the software vendor for support. Error status 0xc000012f."

At this point I was frustrated, so I just let it run anyway. Again it completed, but when I went to play my game, it said the lighting needs to be rebuilt. This is very annoying, does anybody know a way to fix it other than redownloading Unreal Engine?

A quick internet search tells me that this error is most probably caused by malware.