After an unfortunate incident involving a crash and a lost save file, I decided to write a batch script to automatically back up my Subnautica 2 saves every x number of minutes. You’ll need 7-Zip and PowerShell installed.

This script will check if Subnautica 2 is running, and if so, will zip the Subnautica save folder to whatever folder the script is located.

@echo off

:loop

rem Get HH:MM:SS for log prefix
FOR /F "tokens=* USEBACKQ" %%F IN (`powershell get-date -format ^"{HH:mm:ss}^"`) DO (
	SET logtime=%%F
)

rem Determine if subnautica is running
tasklist /fi "ImageName eq SubnauticaZero.exe" /fo csv 2>NUL | find /I "SubnauticaZero.exe">NUL

rem If subnautica is running...
if "%ERRORLEVEL%"=="0" (

	rem Get current datetime https://stackoverflow.com/a/2854857
	FOR /F "tokens=* USEBACKQ" %%F IN (`powershell get-date -format ^"{yyyy_MM_dd_HH_mm_ss}^"`) DO (
		SET mydatetime=%%F
	)

	rem Set up a folder name for our new backup
	SET stamp=slot0000-%mydatetime%.zip

	rem Back up with 7zip
	"C:\Program Files\7-Zip\7z.exe" a -tzip "%stamp%" "%USERPROFILE%\AppData\LocalLow\Unknown Worlds\Subnautica Below Zero\SubnauticaZero\SavedGames\slot0000" > NUL

	echo [%logtime%] Backed up to %stamp%
) else (
	echo [%logtime%] Not running...
)

rem sleep for 30 minutes https://stackoverflow.com/a/16803409
powershell -command "Start-Sleep -s 1800"

goto loop

To run the script simply save the above code into a file with a filename like backup.bat and double click it. Run it whenever you’re playing and close it when you’re done.