setlocal EnableDelayedExpansion
set TO=120
:BEG
@set vmb=
@for /F %%a in ('uwfmgr overlay get-availablespace ^| findstr /R ".[0-9].[0-9]...M.B...a.v.a" ^|  more ^|  findstr ^[0-9]') do @set vmb=!vmb!%%a
setx /M UWFMGRVOL %vmb%
@rem reg query  "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v UWFMGRVOL
timeout /t %TO% 
GOTO BEG