diff --git modules/forum/forum.install modules/forum/forum.install
index 22b8d46..ae9560c 100644
--- modules/forum/forum.install
+++ modules/forum/forum.install
@@ -24,6 +24,10 @@ function forum_install() {
  * Implements hook_enable().
  */
 function forum_enable() {
+  // If we enable forum at the same time as taxonomy we need to call
+  // field_associate_field as otherwise the field won't be enabled until
+  // hook modules_enabled is called which takes place after hook_enable events.
+  field_associate_fields('taxonomy');
   // Create the forum vocabulary if it does not exist.
   $vocabulary = taxonomy_vocabulary_load(variable_get('forum_nav_vocabulary', 0));
   if (!$vocabulary) {
@@ -56,28 +60,6 @@ function forum_enable() {
     );
     field_create_field($field);
 
-    $instance = array(
-      'field_name' => 'taxonomy_' . $vocabulary->machine_name,
-      'entity_type' => 'node',
-      'label' => $vocabulary->name,
-      'bundle' => 'forum',
-      'required' => TRUE,
-      'widget' => array(
-        'type' => 'options_select',
-      ),
-      'display' => array(
-        'default' => array(
-          'type' => 'taxonomy_term_reference_link',
-          'weight' => 10,
-        ),
-        'teaser' => array(
-          'type' => 'taxonomy_term_reference_link',
-          'weight' => 10,
-        ),
-      ),
-    );
-    field_create_instance($instance);
-
     variable_set('forum_nav_vocabulary', $vocabulary->vid);
 
     // Create a default forum so forum posts can be created.
@@ -90,6 +72,30 @@ function forum_enable() {
     $term = (object) $edit;
     taxonomy_term_save($term);
   }
+
+  // Create the instance on the bundle.
+  $instance = array(
+    'field_name' => 'taxonomy_' . $vocabulary->machine_name,
+    'entity_type' => 'node',
+    'label' => $vocabulary->name,
+    'bundle' => 'forum',
+    'required' => TRUE,
+    'widget' => array(
+      'type' => 'options_select',
+    ),
+    'display' => array(
+      'default' => array(
+        'type' => 'taxonomy_term_reference_link',
+        'weight' => 10,
+      ),
+      'teaser' => array(
+        'type' => 'taxonomy_term_reference_link',
+        'weight' => 10,
+      ),
+    ),
+  );
+  field_create_instance($instance);
+
   // Ensure the forum node type is available.
   node_types_rebuild();
   $types = node_type_get_types();
diff --git modules/system/system.test modules/system/system.test
index 6ae3989..d0f803f 100644
--- modules/system/system.test
+++ modules/system/system.test
@@ -218,7 +218,7 @@ class ModuleDependencyTestCase extends ModuleTestCase {
     $edit = array();
     $edit['modules[Core][translation][enable]'] = 'translation';
     $this->drupalPost('admin/modules', $edit, t('Save configuration'));
-    $this->assertText(t('Some required modules must be enabled'), t('Dependecy required.'));
+    $this->assertText(t('Some required modules must be enabled'), t('Dependency required.'));
 
     $this->assertModules(array('translation', 'locale'), FALSE);
 
@@ -285,6 +285,39 @@ class ModuleDependencyTestCase extends ModuleTestCase {
     $this->assertModules(array('comment'), TRUE);
 
   }
+
+  /**
+   * Tests re-enabling forum with taxonomy disabled.
+   */
+  function testEnableForumTaxonomyFieldDependency() {
+    // Enable the forum module.
+    $edit = array();
+    $edit['modules[Core][forum][enable]'] = 'forum';
+    $this->drupalPost('admin/modules', $edit, t('Save configuration'));
+    $this->assertModules(array('forum'), TRUE);
+
+    // Disable the forum module.
+    $edit = array();
+    $edit['modules[Core][forum][enable]'] = FALSE;
+    $this->drupalPost('admin/modules', $edit, t('Save configuration'));
+    $this->assertModules(array('forum'), FALSE);
+
+    // Disable the taxonomy module.
+    $edit = array();
+    $edit['modules[Core][taxonomy][enable]'] = FALSE;
+    $this->drupalPost('admin/modules', $edit, t('Save configuration'));
+    $this->assertModules(array('taxonomy'), FALSE);
+
+    // Attempt to re-enable the forum module with taxonomy disabled and ensure
+    // forum does not try to recreate the taxonomy_forums field.
+    $edit = array();
+    $edit['modules[Core][forum][enable]'] = 'forum';
+    $this->drupalPost('admin/modules', $edit, t('Save configuration'));
+    $this->assertText(t('Some required modules must be enabled'), t('Dependency required.'));
+    $this->drupalPost(NULL, NULL, t('Continue'));
+    $this->assertText(t('The configuration options have been saved.'), t('Modules status has been updated.'));
+    $this->assertModules(array('taxonomy', 'forum'), TRUE);
+  }
 }
 
 /**