Код:

@Echo Off
cls
Set "BoxIn=Z:\Box_In"
FOR /F "usebackq delims=" %%f In (`2^>nul Dir /B /A:-D "%BoxIn%\*_20??-??-??.*"`) DO If Exist "%BoxIn%\%%f" (
Set "Name=%%~nf"
Call Echo %%Name%%|>nul 2>&1 FindStr/I /R /C:"^.*_20[0-9][0-9]-[0-1][0-9]-[0-3][0-9]$"&& (
Call Set "Name=%%Name:~0,-11%%"
Call 2>nul Md "%BoxIn%\%%Name%%"
Call >nul Move /Y "%BoxIn%\%%Name%%_20??-??-??.*" "%BoxIn%\%%Name%%\"
))
Pause
Exit /B
То же, чуть проще и быстрее, но менее надёжно
Код:

@Echo Off
cls
Set "BoxIn=Z:\Box_In"
FOR /F "usebackq delims=" %%f In (`2^>nul Dir /B /A:-D "%BoxIn%\*_20??-??-??.*"`) DO If Exist "%BoxIn%\%%f" (
Set "Name=%%~nf"
Call Set "Name=%%Name:~0,-11%%"
Call 2>nul Md "%BoxIn%\%%Name%%"
Call >nul Move /Y "%BoxIn%\%%Name%%_20??-??-??.*" "%BoxIn%\%%Name%%\"
)
Pause
Exit /B