The original "Windows Defender" is only for Windows Vista and Windows 7.
You should select "Microsoft Security Essentials" to get virus definition updates for Windows 8 and higher. You don't need the installers, but the virus definition files are the same for MSSE as for Windows 8 and higher.
The antivirus software of Windows 8 is sometimes also called "Defender", but if you select "Windows Defender definition updates", it will be changed to "Microsoft Security Essentials" internally, depending on the Windows version.
This is from DownloadUpdates.cmd, as of version 10.0, starting at line 151:
- Code: Select all
if /i "%3"=="/includemsse" set INC_MSSE=1
if /i "%3"=="/includewddefs" (
echo %1 | %SystemRoot%\System32\find.exe /I "w62" >nul 2>&1
if errorlevel 1 (
echo %1 | %SystemRoot%\System32\find.exe /I "w63" >nul 2>&1
if errorlevel 1 (
echo %1 | %SystemRoot%\System32\find.exe /I "w100" >nul 2>&1
if errorlevel 1 (set INC_WDDEFS=1) else (set INC_MSSE=1)
) else (set INC_MSSE=1)
)
)
So, it is not a bug, but I find this slightly confusing myself.