diff --git a/.gitignore b/.gitignore
index 620fc0fc..118a3dea 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,6 @@ __pycache__/
 test/fixtures/testproj/project/project/
 test/fixtures/testproj/project/target/
 test/fixtures/testproj/target/
+test/fixtures/testproj-noplugin/project/project/
+test/fixtures/testproj-noplugin/project/target/
+test/fixtures/testproj-noplugin/target/
diff --git a/lib/index.js b/lib/index.js
index e54ca81c..458931d0 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,6 +1,6 @@
 var path = require('path');
 var subProcess = require('./sub-process');
-var parse = require('./parse-sbt');
+var parser = require('./parse-sbt');
 var packageFormatVersion = 'mvn:0.0.1';
 
 module.exports = {
@@ -15,7 +15,7 @@ function inspect(root, targetFile, options) {
   .then(function (result) {
     var packageName = path.basename(root);
     var packageVersion = '0.0.0';
-    var depTree = parse(result, packageName, packageVersion);
+    var depTree = parser.parse(result, packageName, packageVersion);
     depTree.packageFormatVersion = packageFormatVersion;
 
     return {
@@ -25,6 +25,13 @@ function inspect(root, targetFile, options) {
       },
       package: depTree,
     };
+  })
+  .catch(function (error) {
+    var thrownError = parser.parseError(error);
+    if (thrownError) {
+      throw thrownError;
+    }
+    throw new Error('An unknown error occurred.');
   });
 }
 
diff --git a/lib/parse-sbt.js b/lib/parse-sbt.js
index 884aa433..3fb75677 100644
--- a/lib/parse-sbt.js
+++ b/lib/parse-sbt.js
@@ -93,6 +93,14 @@ function convertDepArrayToObject(depsArr) {
   }, {});
 }
 
+function parseError(text) {
+  if (text.indexOf('Not a valid command: dependency-tree') !== -1) {
+    return new Error('Plugin missing `sbt-dependency-graph` ' +
+      '(https://github.com/jrudolph/sbt-dependency-graph). ' +
+      'Please install it globally or on the current project and try again.');
+  }
+}
+
 function parse(text, name, version) {
   var tree = converStrToTree(text);
   var snykTree = {
@@ -105,4 +113,7 @@ function parse(text, name, version) {
   return snykTree;
 }
 
-module.exports = parse;
+module.exports = {
+  parse: parse,
+  parseError: parseError,
+};
diff --git a/package.json b/package.json
index 85ea0338..d6524c22 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "test": "npm run lint && npm run test-functional",
     "lint": "jscs `find ./lib -name '*.js'` -v && jscs `find ./test -name '*.js'` -v",
     "test-functional": "tap `find ./test/functional -name '*.test.js'`",
-    "test-system": "tap `find ./test/system -name '*.test.js'`",
+    "test-system": "tap --timeout=300 `find ./test/system -name '*.test.js'`",
     "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
   "author": "snyk.io",
diff --git a/test/fixtures/sbt-no-plugin-output.txt b/test/fixtures/sbt-no-plugin-output.txt
new file mode 100644
index 00000000..915b3a86
--- /dev/null
+++ b/test/fixtures/sbt-no-plugin-output.txt
@@ -0,0 +1,8 @@
+[info] Loading global plugins from /Users/dror/.sbt/0.13/plugins/project
+[info] Loading global plugins from /Users/dror/.sbt/0.13/plugins
+[info] Loading project definition from /Users/dror/work/snyk/snyk-sbt-plugin/test/fixtures/testproj-noplugin/project
+[info] Set current project to Hello (in build file:/Users/dror/work/snyk/snyk-sbt-plugin/test/fixtures/testproj-noplugin/)
+[error] Not a valid command: dependency-tree
+[error] Not a valid key: dependency-tree (similar: dependency-overrides, dependencyOverrides, dependency-classpath)
+[error] dependency-tree
+[error]                ^
diff --git a/test/fixtures/testproj-noplugin/build.sbt b/test/fixtures/testproj-noplugin/build.sbt
new file mode 100644
index 00000000..a35abef2
--- /dev/null
+++ b/test/fixtures/testproj-noplugin/build.sbt
@@ -0,0 +1,10 @@
+lazy val root = (project in file(".")).
+  settings(
+    inThisBuild(List(
+      organization := "com.example",
+      scalaVersion := "2.12.1",
+      version      := "0.1.0-SNAPSHOT"
+    )),
+    name := "Hello",
+    libraryDependencies += "axis" % "axis" % "1.4"
+  )
diff --git a/test/fixtures/testproj-noplugin/project/build.properties b/test/fixtures/testproj-noplugin/project/build.properties
new file mode 100644
index 00000000..27e88aa1
--- /dev/null
+++ b/test/fixtures/testproj-noplugin/project/build.properties
@@ -0,0 +1 @@
+sbt.version=0.13.13
diff --git a/test/fixtures/testproj-noplugin/project/site.sbt b/test/fixtures/testproj-noplugin/project/site.sbt
new file mode 100644
index 00000000..e69de29b
diff --git a/test/fixtures/testproj-noplugin/src/main/scala/example/Hello.scala b/test/fixtures/testproj-noplugin/src/main/scala/example/Hello.scala
new file mode 100644
index 00000000..80ea40a9
--- /dev/null
+++ b/test/fixtures/testproj-noplugin/src/main/scala/example/Hello.scala
@@ -0,0 +1,9 @@
+package example
+
+object Hello extends Greeting with App {
+  println(greeting)
+}
+
+trait Greeting {
+  lazy val greeting: String = "hello"
+}
diff --git a/test/functional/parse-sbt.test.js b/test/functional/parse-sbt.test.js
index fe418d7e..526d481a 100644
--- a/test/functional/parse-sbt.test.js
+++ b/test/functional/parse-sbt.test.js
@@ -1,12 +1,13 @@
-var test = require('tap-only');
-var parse = require('../../lib/parse-sbt');
 var fs = require('fs');
+var path = require('path');
+var test = require('tap-only');
+var parser = require('../../lib/parse-sbt');
 
 test('parse a `sbt dependencies` output', function (t) {
   t.plan(4);
-  var sbtOutput = fs.readFileSync(
-    __dirname + '/../fixtures/sbt-dependency-output.txt', 'utf8');
-  var depTree = parse(sbtOutput, 'testApp', '1.0.1');
+  var sbtOutput = fs.readFileSync(path.join(
+    __dirname, '..', 'fixtures', 'sbt-dependency-output.txt'), 'utf8');
+  var depTree = parser.parse(sbtOutput, 'testApp', '1.0.1');
 
   t.equal(depTree
     .dependencies['myproject-common:myproject-common_2.11']
@@ -44,3 +45,12 @@ test('parse a `sbt dependencies` output', function (t) {
     ],
     '`from` array is good');
 });
+
+
+test('parse an error output', function (t) {
+  t.plan(1);
+  var sbtOutput = fs.readFileSync(path.join(
+    __dirname, '..', 'fixtures', 'sbt-no-plugin-output.txt'), 'utf8');
+  var error = parser.parseError(sbtOutput, 'testApp', '1.0.1');
+  t.type(error, 'object', 'Error thrown correctly');
+});
diff --git a/test/system/plugin.test.js b/test/system/plugin.test.js
index 1ed46d71..1e50b804 100644
--- a/test/system/plugin.test.js
+++ b/test/system/plugin.test.js
@@ -1,11 +1,12 @@
+var fs = require('fs');
+var path = require('path');
 var test = require('tap-only');
 var plugin = require('../../lib');
-var fs = require('fs');
 
 test('run inspect()', function (t) {
   t.plan(1);
-  return plugin.inspect(
-    __dirname + '/../fixtures/testproj/',
+  return plugin.inspect(path.join(
+    __dirname, '..', 'fixtures', 'testproj'),
     'build.sbt')
   .then(function (result) {
     t.equal(result.package
@@ -17,3 +18,13 @@ test('run inspect()', function (t) {
       'correct version found');
   });
 });
+
+test('run inspect() with no sbt plugin', function (t) {
+  t.plan(1);
+  return plugin.inspect(path.join(
+    __dirname, '..', 'fixtures', 'testproj-noplugin'),
+    'build.sbt')
+  .catch(function (result) {
+    t.pass('Error thrown correctly');
+  });
+});