Index: typo3/sysext/install/updates/class.tx_coreupdates_migrateworkspaces.php
===================================================================
--- typo3/sysext/install/updates/class.tx_coreupdates_migrateworkspaces.php	(revision 10084)
+++ typo3/sysext/install/updates/class.tx_coreupdates_migrateworkspaces.php	(working copy)
@@ -50,19 +50,35 @@
 		migrates the old-style workspaces with fixed workflow to a custom-stage workflow. If required
 		the extbase, fluid, version and workspaces extensions are installed.';
 
+		$reason = '';
 			// TYPO3 version 4.5 and above
 		if ($this->versionNumber >= 4005000) {
+
+			 if(!t3lib_extMgm::isLoaded('version') || !t3lib_extMgm::isLoaded('workspaces')) {
+				$result = true;
+				$reason .= ' The extensions "version" and "workspaces" need to be
+					present to use the entire versioning and workflow featureset of TYPO3.';
+			 }
+
 			$tables = array_keys($GLOBALS['TYPO3_DB']->admin_get_tables());
 				// sys_workspace table might not exists if version extension was never installed
-			if (in_array('sys_workspace', $tables)) {
+			if (!in_array('sys_workspace', $tables) || !in_array('sys_workspace_stages', $tables)) {
+				$result = true;
+				$reason .= ' The database tables for the workspace functionality are missing.';
+			} else {
 				$wsCount = $GLOBALS['TYPO3_DB']->exec_SELECTcountRows('uid', 'sys_workspace', '');
 				$result = $wsCount > 0;
+				$reason .= ' The existing workspaces need to be checked for compatibility with the new features.';
 			}
 
 			if (!$result) {
 				$this->includeTCA();
 				$result = $this->isDraftWorkspaceUsed();
+				$reason .= ' The old style draft workspace is used.
+					Related records will be moved into a full featured workspace.';
 			}
+
+			$description .= '<strong>Why do you need this wizard?</strong><br />' . $reason;
 		}
 
 		return $result;