diff --git a/cmd/sii-missing-classes/go.mod b/cmd/sii-missing-classes/go.mod
new file mode 100644
index 0000000..9ddeac6
--- /dev/null
+++ b/cmd/sii-missing-classes/go.mod
@@ -0,0 +1,12 @@
+module github.com/Luzifer/sii/cmd/sii-missing-classes
+
+go 1.13
+
+replace github.com/Luzifer/sii => ../../
+
+require (
+	github.com/Luzifer/go_helpers/v2 v2.10.0
+	github.com/Luzifer/rconfig/v2 v2.2.1
+	github.com/Luzifer/sii v0.0.0-20191211000354-9e3185ab7f66
+	github.com/sirupsen/logrus v1.4.2
+)
diff --git a/cmd/sii-missing-classes/go.sum b/cmd/sii-missing-classes/go.sum
new file mode 100644
index 0000000..ad91385
--- /dev/null
+++ b/cmd/sii-missing-classes/go.sum
@@ -0,0 +1,25 @@
+github.com/Luzifer/go_helpers/v2 v2.10.0 h1:rA3945P6tH1PKRdcVD+nAdAWojfgwX8wQm/jjUNPmfg=
+github.com/Luzifer/go_helpers/v2 v2.10.0/go.mod h1:ZnWxPjyCdQ4rZP3kNiMSUW/7FigU1X9Rz8XopdJ5ZCU=
+github.com/Luzifer/rconfig/v2 v2.2.1 h1:zcDdLQlnlzwcBJ8E0WFzOkQE1pCMn3EbX0dFYkeTczg=
+github.com/Luzifer/rconfig/v2 v2.2.1/go.mod h1:OKIX0/JRZrPJ/ZXXWklQEFXA6tBfWaljZbW37w+sqBw=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/inconshreveable/go-update v0.0.0-20160112193335-8152e7eb6ccf/go.mod h1:hyb9oH7vZsitZCiBt0ZvifOrB+qc8PS5IiilCIb87rg=
+github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
+github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
+github.com/leekchan/gtf v0.0.0-20190214083521-5fba33c5b00b/go.mod h1:thNruaSwydMhkQ8dXzapABF9Sc1Tz08ZBcDdgott9RA=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
+github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
+github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
+github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
+github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/pU5OE2C0WrNTOYK1Uuc=
+golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/validator.v2 v2.0.0-20180514200540-135c24b11c19 h1:WB265cn5OpO+hK3pikC9hpP1zI/KTwmyMFKloW9eOVc=
+gopkg.in/validator.v2 v2.0.0-20180514200540-135c24b11c19/go.mod h1:o4V0GXN9/CAmCsvJ0oXYZvrZOe7syiDZSN1GWGZTGzc=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/cmd/sii-missing-classes/main.go b/cmd/sii-missing-classes/main.go
new file mode 100644
index 0000000..a01a0e2
--- /dev/null
+++ b/cmd/sii-missing-classes/main.go
@@ -0,0 +1,82 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"reflect"
+	"sort"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/Luzifer/go_helpers/v2/str"
+	"github.com/Luzifer/sii"
+
+	"github.com/Luzifer/rconfig/v2"
+)
+
+var (
+	cfg = struct {
+		LogLevel       string `flag:"log-level" default:"info" description:"Log level (debug, info, warn, error, fatal)"`
+		VersionAndExit bool   `flag:"version" default:"false" description:"Prints current version and exits"`
+	}{}
+
+	version = "dev"
+)
+
+func init() {
+	if err := rconfig.ParseAndValidate(&cfg); err != nil {
+		log.Fatalf("Unable to parse commandline options: %s", err)
+	}
+
+	if cfg.VersionAndExit {
+		fmt.Printf("sii-missing-blocks %s\n", version)
+		os.Exit(0)
+	}
+
+	if l, err := log.ParseLevel(cfg.LogLevel); err != nil {
+		log.WithError(err).Fatal("Unable to parse log level")
+	} else {
+		log.SetLevel(l)
+	}
+}
+
+func main() {
+	if len(rconfig.Args()) != 2 {
+		log.Fatal("Missing filename to analyze")
+	}
+
+	filename := rconfig.Args()[1]
+
+	log.WithField("filename", filename).Info("Loading file")
+	unit, err := sii.ReadUnitFile(filename)
+	if err != nil {
+		log.Fatalf("Unable to parse input file: %s", err)
+	}
+
+	var unknownClasses []string
+
+	for _, e := range unit.Entries {
+		if reflect.TypeOf(e).Elem() == reflect.TypeOf(sii.RawBlock{}) {
+			log.WithFields(log.Fields{
+				"class": e.Class(),
+				"name":  e.Name(),
+			}).Debug("Found raw block")
+
+			if !str.StringInSlice(e.Class(), unknownClasses) {
+				unknownClasses = append(unknownClasses, e.Class())
+			}
+		}
+	}
+
+	if len(unknownClasses) == 0 {
+		log.Info("No unknown classes found")
+		return
+	}
+
+	sort.Strings(unknownClasses)
+
+	log.WithField("count", len(unknownClasses)).Info("Found unknown classes")
+
+	fmt.Println(strings.Join(unknownClasses, "\n"))
+}