After an update to the Google Drive desktop software, it refused to download new files created online or on another device but changes to existing files where reflected correctly.
I solved it by starting the process with a different “TEMP” environment variable:
C:\Windows\System32\cmd.exe /c
"SET TEMP=C:\Temp &&
START /D ^"C:\Program Files (x86)\Google\Drive\^" googledrivesync.exe"