diff --git a/base/src/main/java/de/staropensource/sosengine/base/utility/DependencyResolver.java b/base/src/main/java/de/staropensource/sosengine/base/utility/DependencyResolver.java
index 463852c..168a23d 100644
--- a/base/src/main/java/de/staropensource/sosengine/base/utility/DependencyResolver.java
+++ b/base/src/main/java/de/staropensource/sosengine/base/utility/DependencyResolver.java
@@ -124,19 +124,27 @@ public final class DependencyResolver {
      * Throws an exception when detecting an unmet dependency or a dependency cycle.
      *
      * @return itself
-     * @throws UnmetDependenciesException   when dependencies are unmet
+     * @throws IllegalStateException when encountering an invalid vector
+     * @throws UnmetDependenciesException when dependencies are unmet
      * @since v1-alpha1
      */
-    public synchronized DependencyResolver resolve() throws UnmetDependenciesException {
-        Map<DependencyVector, String> unmetDependencies = new HashMap<>();
+    public synchronized DependencyResolver resolve() throws IllegalStateException, UnmetDependenciesException {
+        Map<@NotNull DependencyVector, @NotNull String> unmetDependencies = new HashMap<>();
+        List<@NotNull String> output;
 
         for (DependencyVector vector : vectors) {
             if (!vectorsResolved.contains(vector.getIdentifier())) {
-                resolveVector(vector);
+                output = resolveVector(vector);
+                for (String item : output)
+                    unmetDependencies.put(vector, item);
+
                 vectorsResolved.add(vector.getIdentifier());
             }
         }
 
+        if (!unmetDependencies.isEmpty())
+            throw new UnmetDependenciesException(unmetDependencies);
+
         resolved = true;
         return this;
     }
@@ -146,8 +154,8 @@ public final class DependencyResolver {
      * Throws an exception when detecting an unmet dependency or a dependency cycle.
      *
      * @return list of unmet dependencies
-     * @throws IllegalStateException        when encountering an invalid dependency or provider
-     * @throws Exception                    when some unknown error occurs
+     * @throws IllegalStateException when encountering an invalid dependency or provider
+     * @throws Exception             when some unknown error occurs
      * @since v1-alpha4
      */
     private @NotNull List<@NotNull String> resolveVector(@NotNull DependencyVector vector) throws IllegalStateException {
@@ -274,7 +282,7 @@ public final class DependencyResolver {
                 // Compare versions
                 if (versioningSystemResolved.compare(versioningSystemEquals) != 1)
                     unmetDependencies.add("Dependency \"" + dependency + "\" is not met: Expected version " + versionEqual + " does not match found version " + vector.getVersion());
-            } else {
+            } else if (!versionBigger.isEmpty() || !versionSmaller.isEmpty()) {
                 VersioningSystem versioningSystemSmaller = null;
                 VersioningSystem versioningSystemBigger = null;
 
@@ -297,14 +305,14 @@ public final class DependencyResolver {
 
                 // Compare versions
                 if (versioningSystemSmaller != null && versioningSystemBigger != null) {
-                    if (versioningSystemResolved.compare(versioningSystemSmaller) != 0 && versioningSystemResolved.compare(versioningSystemBigger) != 2)
+                    if (versioningSystemResolved.compare(versioningSystemSmaller) != 2 || versioningSystemResolved.compare(versioningSystemBigger) != 0)
                         unmetDependencies.add("Dependency \"" + dependency + "\" is not met: Version " + vector.getVersion() + " is not in range " + versionSmaller + " to " + versionBigger);
                 } else {
                     if (versioningSystemSmaller != null)
-                        if (versioningSystemResolved.compare(versioningSystemSmaller) != 0)
+                        if (versioningSystemResolved.compare(versioningSystemSmaller) != 2)
                             unmetDependencies.add("Dependency \"" + dependency + "\" is not met: Version " + vector.getVersion() + " is bigger than " + versionSmaller);
                     if (versioningSystemBigger != null)
-                        if (versioningSystemResolved.compare(versioningSystemBigger) != 2)
+                        if (versioningSystemResolved.compare(versioningSystemBigger) != 0)
                             unmetDependencies.add("Dependency \"" + dependency + "\" is not met: Version " + vector.getVersion() + " is smaller than " + versionBigger);
                 }
             }