I would like to restart the AFP service but I'm not sure how to do it anymore. In previous versions of OS X I would run
serveradmin stop afp and
serveradmin start afp, but
serveradmin is no longer available in High Sierra.
serveradmin is still available in macOS High Sierra. Server.app has to be installed though and launched at least once to start its set-up.
host:~ $user: which serveradmin /Applications/Server.app/Contents/ServerRoot/usr/sbin/serveradmin host:~ $user: sudo serveradmin fullstatus afp afp:state = "STOPPED" afp:readWriteSettingsVersion = 1 afp:logging = "NO" afp:servicePortsRestrictionInfo = _empty_array afp:startedTime = "" afp:guestAccess = "NO" afp:logPaths:errorLog = "/Library/Logs/AppleFileService/AppleFileServiceError.log" afp:logPaths:accessLog = "/Library/Logs/AppleFileService/AppleFileServiceAccess.log" afp:failoverState = "NIFailoverNotConfigured" afp:servicePortsAreRestricted = "NO" afp:setStateVersion = 2 afp:currentConnections = 0
AFP won't work with shared APFS volumes!
System Preferences -> Sharing would allow you to turn off all file sharing, then turn it on again.