Try this
d:\temp\archiveTool\archivetool.exe “D:\temp\gquest\newarcs\creatures.arc” -add . “d:\temp\archiveTool\creatures” 9
Sorry, there was a typo (space before " instead of 9)
This worked for me on my computer (not Windows command line so paths format might differ):
/C/Program\ Files\ (x86)/Steam/steamapps/common/Grim\ Dawn/ArchiveTool.exe Scripts.arc -add . “C:\Users\MY_USERNAME\Desktop\scripts” 9
- Scripts.arc is created with proper size in my current command line directory
- from scripts folder that’s on Desktop