A .dll file may be found missing or corrupted by many possible reasons. They include: The installation of any new .dll file could have over written the existed one thus with newer files being installed, the older file might have been replaced by it. Also one more reason might be because of uninstalling any program which was necessary to run or for the working of .dll file. This could have corrupted the previous file making it missing. Or if any other files or program were not properly installed, this eventually leads to the corruption of some of the .dll files in the system. If the system is being handled by many persons, the others might have removed the file by mistake when handling its related files. Occasionally it could be due to the hardware problems in the computer also. The drive used could have errors leading to the missing of the .dll files.