Error Fastboot AdbWinApi.dll is Missing, How To Fix?

What Is AdbWinApi.dll?

AdbWinApi.dll is a type of DLL file associated with Android SDK developed by China Mobile for the Windows Operating System. The latest known version of AdbWinApi.dll is, which was produced for Windows. This DLL file carries a popularity rating of 2 stars and a security rating of "UNKNOWN".

You have to installed Android SDK on your PC and here is the download link
2. Go to sdk installed folder, and then to Platform tools folder
(ex: c:\android-sdk-windows\platform tools)

there copy those 3 files to your c:\android. That's enough...
1. adb.exe
2. adbWinApi.dll
3. Fastboot.exe

You dont have to move the complete folder, just copy those 3 files.