It’s rare, but the occasional customer has a problem where the license server keeps stopping (for example, after the computer goes to sleep). Normally the license service should always be running, but if you were really stuck and needed a workaround, you could add something to XSI.bat to start the license server before starting xsi.exe.
For example, here’s something I got from stackoverflow. You probably could just call sc start; if the service is already running, sc will just report that and nothing bad will happen.
@echo off for /F "tokens=3 delims=: " %%H in ('sc query "Softimage License Server" ^| findstr "STATE"') do ( if /I "%%H" NEQ "RUNNING" ( sc start "Softimage License Server" echo "Starting Softimage License Server" ) )