When the log path directory contains spaces and you install the service like so:

mongod.exe --install --logpath "c:\my path\has spaces\in it\log.log" --dbpath "c:\my path\has spaces\also in it\"

Then it installs fine, but the service cannot be started. When you look at the service properties, the executable path looks like so:

"c:\my path\has spaces\in it\mongod.exe" --service --logpath c:\my path\has spaces\in it\log.log --dbpath "c:\my path\has spaces\also in it\""