Index: t3lib/class.t3lib_page.php
===================================================================
--- t3lib/class.t3lib_page.php	(Revision 10349)
+++ t3lib/class.t3lib_page.php	(Arbeitskopie)
@@ -1414,7 +1414,7 @@
 	 * @return	boolean	<code>true</code> if has access
 	 */
 	function checkWorkspaceAccess($wsid) {
-		if (!$GLOBALS['BE_USER']) {
+		if (!$GLOBALS['BE_USER'] || !t3lib_extMgm::isLoaded('workspaces')) {
 			return FALSE;
 		}
 		if (isset($this->workspaceCache[$wsid])) {
Index: t3lib/class.t3lib_userauthgroup.php
===================================================================
--- t3lib/class.t3lib_userauthgroup.php	(Revision 10349)
+++ t3lib/class.t3lib_userauthgroup.php	(Arbeitskopie)
@@ -876,7 +876,7 @@
 			return TRUE;
 		}
 
-		if ($this->workspace > 0) {
+		if ($this->workspace > 0 && t3lib_extMgm::isLoaded('workspaces')) {
 			$stat = $this->checkWorkspaceCurrent();
 
 				// Check if custom staging is activated
@@ -1645,14 +1645,16 @@
 					$wsRec = array('uid' => $wsRec);
 				break;
 				default:
-					$wsRec = $GLOBALS['TYPO3_DB']->exec_SELECTgetSingleRow(
-						$fields,
-						'sys_workspace',
-						'pid=0 AND uid=' . intval($wsRec) .
-						t3lib_BEfunc::deleteClause('sys_workspace'),
-						'',
-						'title'
-					);
+					if (t3lib_extMgm::isLoaded('workspaces')) {
+						$wsRec = $GLOBALS['TYPO3_DB']->exec_SELECTgetSingleRow(
+							$fields,
+							'sys_workspace',
+							'pid=0 AND uid=' . intval($wsRec) .
+							t3lib_BEfunc::deleteClause('sys_workspace'),
+							'',
+							'title'
+						);
+					}
 				break;
 			}
 		}
@@ -1772,7 +1774,7 @@
 			return 0;
 		} elseif ($this->checkWorkspace(-1)) { // Check offline
 			return -1;
-		} else { // Traverse custom workspaces:
+		} elseif (t3lib_extMgm::isLoaded('workspaces')) { // Traverse custom workspaces:
 			$workspaces = $GLOBALS['TYPO3_DB']->exec_SELECTgetRows('uid,title,adminusers,members,reviewers', 'sys_workspace', 'pid=0' . t3lib_BEfunc::deleteClause('sys_workspace'), '', 'title');
 			foreach ($workspaces as $rec) {
 				if ($this->checkWorkspace($rec)) {
Index: typo3/alt_shortcut.php
===================================================================
--- typo3/alt_shortcut.php	(Revision 10349)
+++ typo3/alt_shortcut.php	(Arbeitskopie)
@@ -736,11 +736,13 @@
 		}
 
 			// Add custom workspaces (selecting all, filtering by BE_USER check):
-		$workspaces = $TYPO3_DB->exec_SELECTgetRows('uid,title,adminusers,members,reviewers','sys_workspace','pid=0'.t3lib_BEfunc::deleteClause('sys_workspace'),'','title');
-		if (count($workspaces))	{
-			foreach ($workspaces as $rec)	{
-				if ($BE_USER->checkWorkspace($rec))	{
-					$options[$rec['uid']] = $rec['uid'].': '.$rec['title'];
+		if (t3lib_extMgm::isLoaded('workspaces')) {
+			$workspaces = $TYPO3_DB->exec_SELECTgetRows('uid,title,adminusers,members,reviewers','sys_workspace','pid=0'.t3lib_BEfunc::deleteClause('sys_workspace'),'','title');
+			if (count($workspaces))	{
+				foreach ($workspaces as $rec)	{
+					if ($BE_USER->checkWorkspace($rec))	{
+						$options[$rec['uid']] = $rec['uid'].': '.$rec['title'];
+					}
 				}
 			}
 		}
Index: typo3/sysext/beuser/mod/index.php
===================================================================
--- typo3/sysext/beuser/mod/index.php	(Revision 10349)
+++ typo3/sysext/beuser/mod/index.php	(Arbeitskopie)
@@ -1048,18 +1048,20 @@
 		}
 
 			// Add custom workspaces (selecting all, filtering by BE_USER check):
-		$workspaces = $GLOBALS['TYPO3_DB']->exec_SELECTgetRows('uid,title,adminusers,members,reviewers,db_mountpoints','sys_workspace','pid=0'.t3lib_BEfunc::deleteClause('sys_workspace'),'','title');
-		if (count($workspaces))	{
-			foreach ($workspaces as $rec)	{
-				if ($this->checkWorkspace($rec))	{
-					$options[$rec['uid']] = $rec['uid'].': '.$rec['title'];
+		if (t3lib_extMgm::isLoaded('workspaces')) {
+			$workspaces = $GLOBALS['TYPO3_DB']->exec_SELECTgetRows('uid,title,adminusers,members,reviewers,db_mountpoints','sys_workspace','pid=0'.t3lib_BEfunc::deleteClause('sys_workspace'),'','title');
+			if (count($workspaces))	{
+				foreach ($workspaces as $rec)	{
+					if ($this->checkWorkspace($rec))	{
+						$options[$rec['uid']] = $rec['uid'].': '.$rec['title'];
 
-						// Check if all mount points are accessible, otherwise show error:
-					if (trim($rec['db_mountpoints'])!=='')	{
-						$mountPoints = t3lib_div::intExplode(',',$this->workspaceRec['db_mountpoints'],1);
-						foreach ($mountPoints as $mpId)	{
-							if (!$this->isInWebMount($mpId,'1=1'))	{
-								$options[$rec['uid']].= '<br> \- ' . $GLOBALS['LANG']->getLL('notAccessible', true) . ' ' . $mpId;
+							// Check if all mount points are accessible, otherwise show error:
+						if (trim($rec['db_mountpoints'])!=='')	{
+							$mountPoints = t3lib_div::intExplode(',',$this->workspaceRec['db_mountpoints'],1);
+							foreach ($mountPoints as $mpId)	{
+								if (!$this->isInWebMount($mpId,'1=1'))	{
+									$options[$rec['uid']].= '<br> \- ' . $GLOBALS['LANG']->getLL('notAccessible', true) . ' ' . $mpId;
+								}
 							}
 						}
 					}
Index: typo3/sysext/belog/mod/index.php
===================================================================
--- typo3/sysext/belog/mod/index.php	(Revision 10349)
+++ typo3/sysext/belog/mod/index.php	(Arbeitskopie)
@@ -179,10 +179,12 @@
 		);
 
 		// Add custom workspaces (selecting all, filtering by BE_USER check):
-		$workspaces = $TYPO3_DB->exec_SELECTgetRows('uid,title','sys_workspace','pid=0'.t3lib_BEfunc::deleteClause('sys_workspace'),'','title');
-		if (count($workspaces))	{
-			foreach ($workspaces as $rec)	{
-				$this->MOD_MENU['workspaces'][$rec['uid']] = $rec['uid'].': '.$rec['title'];
+		if (t3lib_extMgm::isLoaded('workspaces')) {
+			$workspaces = $TYPO3_DB->exec_SELECTgetRows('uid,title','sys_workspace','pid=0'.t3lib_BEfunc::deleteClause('sys_workspace'),'','title');
+			if (count($workspaces))	{
+				foreach ($workspaces as $rec)	{
+					$this->MOD_MENU['workspaces'][$rec['uid']] = $rec['uid'].': '.$rec['title'];
+				}
 			}
 		}
 
Index: typo3/sysext/lowlevel/class.tx_lowlevel_cleaner_core.php
===================================================================
--- typo3/sysext/lowlevel/class.tx_lowlevel_cleaner_core.php	(Revision 10349)
+++ typo3/sysext/lowlevel/class.tx_lowlevel_cleaner_core.php	(Arbeitskopie)
@@ -78,7 +78,9 @@
 
 	var $performanceStatistics = array();
 
+	protected $workspaceIndex = array();
 
+
 	/**
 	 * Constructor
 	 *
@@ -332,7 +334,9 @@
 		$pt = t3lib_div::milliseconds();$this->performanceStatistics['genTree()']='';
 
 			// Initialize:
-		$this->workspaceIndex = $GLOBALS['TYPO3_DB']->exec_SELECTgetRows('uid,title','sys_workspace','1=1'.t3lib_BEfunc::deleteClause('sys_workspace'),'','','','uid');
+		if (t3lib_extMgm::isLoaded('workspaces')) {
+			$this->workspaceIndex = $GLOBALS['TYPO3_DB']->exec_SELECTgetRows('uid,title','sys_workspace','1=1'.t3lib_BEfunc::deleteClause('sys_workspace'),'','','','uid');
+		}
 		$this->workspaceIndex[-1] = TRUE;
 		$this->workspaceIndex[0] = TRUE;
 
Index: typo3/sysext/cms/tslib/class.tslib_fe.php
===================================================================
--- typo3/sysext/cms/tslib/class.tslib_fe.php	(Revision 10349)
+++ typo3/sysext/cms/tslib/class.tslib_fe.php	(Arbeitskopie)
@@ -4370,7 +4370,7 @@
 		if ($returnTitle)	{
 			if ($ws===-1)	{
 				return 'Default Draft Workspace';
-			} else {
+			} elseif (t3lib_extMgm::isLoaded('workspaces')) {
 				$res = $GLOBALS['TYPO3_DB']->exec_SELECTquery('title', 'sys_workspace', 'uid='.intval($ws));
 				if ($row = $GLOBALS['TYPO3_DB']->sql_fetch_assoc($res))	{
 					return $row['title'];