diff --git a/src/main/java/org/gcube/portlets/user/workspace/client/AppControllerExplorer.java b/src/main/java/org/gcube/portlets/user/workspace/client/AppControllerExplorer.java
index 6c384ac..8b9730b 100644
--- a/src/main/java/org/gcube/portlets/user/workspace/client/AppControllerExplorer.java
+++ b/src/main/java/org/gcube/portlets/user/workspace/client/AppControllerExplorer.java
@@ -183,7 +183,7 @@ public class AppControllerExplorer implements EventHandler, TreeAppControllerInt
 	
 						@Override
 						public void onFailure(Throwable caught) {
-							new MessageBoxAlert("Error", ConstantsExplorer.SERVER_ERROR+" un share folder. "+ caught.getMessage() +". " +ConstantsExplorer.TRY_AGAIN, null);
+							new MessageBoxAlert("Error", caught.getMessage(), null);
 							
 						}
 	
@@ -279,7 +279,7 @@ public class AppControllerExplorer implements EventHandler, TreeAppControllerInt
 	
 									@Override
 									public void onFailure(Throwable caught) {
-										new MessageBoxAlert("Error", ConstantsExplorer.SERVER_ERROR+" creating shared folder. "+ caught.getMessage(), null);
+										new MessageBoxAlert("Error", caught.getMessage(), null);
 										explorerPanel.unmask();
 									}
 	
@@ -424,7 +424,7 @@ public class AppControllerExplorer implements EventHandler, TreeAppControllerInt
 
 					@Override
 					public void onFailure(Throwable caught) {
-						new MessageBoxAlert("Error", ConstantsExplorer.SERVER_ERROR +" copying item "  + ConstantsExplorer.TRY_AGAIN, null);
+						new MessageBoxAlert("Error", caught.getMessage(), null);
 						
 					}
 
@@ -432,7 +432,6 @@ public class AppControllerExplorer implements EventHandler, TreeAppControllerInt
 					public void onSuccess(Boolean result) {
 						if(result)
 							eventBus.fireEvent(new RefreshFolderEvent(explorerPanel.getAsycTreePanel().getFileModelByIdentifier(pasteItemEvent.getFolderDestinationId())));
-//							explorerPanel.getAsycTreePanel().reloadTreeLevelAndExpandFolder(pasteItemEvent.getFolderDestinationId());
 						
 					}
 				
@@ -873,7 +872,7 @@ public class AppControllerExplorer implements EventHandler, TreeAppControllerInt
 								@Override
 								public void onFailure(Throwable caught) {
 									explorerPanel.getAsycTreePanel().unmask();
-									new MessageBoxAlert("Error", ConstantsExplorer.SERVER_ERROR +" deleting item. "+caught.getMessage()+". Reload root", null);
+									new MessageBoxAlert("Error", caught.getMessage()+". Reload root", null);
 									explorerPanel.getAsycTreePanel().removeAllAndRecoveryRoot();
 									
 								}
@@ -1020,7 +1019,7 @@ public class AppControllerExplorer implements EventHandler, TreeAppControllerInt
 
 					@Override
 					public void onFailure(Throwable caught) {
-						new MessageBoxAlert("Error", ConstantsExplorer.SERVER_ERROR + " moving item. "+caught.getMessage()+". Reload root" , null);
+						new MessageBoxAlert("Error", caught.getMessage()+". Reload root" , null);
 						System.out.println(caught.getMessage());
 						explorerPanel.getAsycTreePanel().reloadTreeLevelAndExpandFolder(event.getTargetParentFileModel().getIdentifier());
 						explorerPanel.getAsycTreePanel().reloadTreeLevelAndExpandFolder(event.getFileSourceModel().getParentFileModel().getIdentifier());
diff --git a/src/main/java/org/gcube/portlets/user/workspace/server/GWTWorkspaceServiceImpl.java b/src/main/java/org/gcube/portlets/user/workspace/server/GWTWorkspaceServiceImpl.java
index 2c6a053..615a609 100644
--- a/src/main/java/org/gcube/portlets/user/workspace/server/GWTWorkspaceServiceImpl.java
+++ b/src/main/java/org/gcube/portlets/user/workspace/server/GWTWorkspaceServiceImpl.java
@@ -17,8 +17,11 @@ import org.gcube.portlets.user.homelibrary.home.workspace.WorkspaceItem;
 import org.gcube.portlets.user.homelibrary.home.workspace.WorkspaceItemType;
 import org.gcube.portlets.user.homelibrary.home.workspace.WorkspaceSharedFolder;
 import org.gcube.portlets.user.homelibrary.home.workspace.WorkspaceSmartFolder;
+import org.gcube.portlets.user.homelibrary.home.workspace.exceptions.InsufficientPrivilegesException;
+import org.gcube.portlets.user.homelibrary.home.workspace.exceptions.ItemAlreadyExistException;
 import org.gcube.portlets.user.homelibrary.home.workspace.exceptions.ItemNotFoundException;
 import org.gcube.portlets.user.homelibrary.home.workspace.exceptions.WorkspaceFolderNotFoundException;
+import org.gcube.portlets.user.homelibrary.home.workspace.exceptions.WrongDestinationException;
 import org.gcube.portlets.user.homelibrary.home.workspace.folder.FolderBulkCreator;
 import org.gcube.portlets.user.homelibrary.home.workspace.folder.FolderItemType;
 import org.gcube.portlets.user.homelibrary.home.workspace.folder.items.ExternalUrl;
@@ -26,6 +29,7 @@ import org.gcube.portlets.user.homelibrary.home.workspace.folder.items.ts.TimeSe
 import org.gcube.portlets.user.homelibrary.home.workspace.search.SearchItem;
 import org.gcube.portlets.user.homelibrary.home.workspace.sharing.WorkspaceMessage;
 import org.gcube.portlets.user.opengcubeapplication.ApplicationReaderFromGenericResource;
+import org.gcube.portlets.user.workspace.client.ConstantsExplorer;
 import org.gcube.portlets.user.workspace.client.interfaces.GXTCategoryItemInterface;
 import org.gcube.portlets.user.workspace.client.model.BulkCreatorModel;
 import org.gcube.portlets.user.workspace.client.model.FileDetailsModel;
@@ -282,11 +286,15 @@ public class GWTWorkspaceServiceImpl extends RemoteServiceServlet implements GWT
 			workspace.moveItem(itemId, destinationId);
 			return Boolean.TRUE;
 
+		}catch (InsufficientPrivilegesException e) {
+			workspaceLogger.error("Error in server Item move", e);
+			String error = "An error occurred on moving item. "+e.getMessage();
+			throw new Exception(error);
+		
 		} catch (Exception e) {
 			workspaceLogger.error("Error in server Item move", e);
-//			workspaceLogger.trace("Error in server Item move " + e);
-			//GWT can't serialize all exceptions
-			throw new Exception(e.getMessage());
+			String error = ConstantsExplorer.SERVER_ERROR + " moving item. "+e.getMessage();
+			throw new Exception(error);
 		}
 
 	}
@@ -302,12 +310,16 @@ public class GWTWorkspaceServiceImpl extends RemoteServiceServlet implements GWT
 
 			workspace.removeItem(itemId);
 			return Boolean.TRUE;
+			
+		} catch (InsufficientPrivilegesException e) {
+			workspaceLogger.error("Error in server Item remove", e);
+			String error = "An error occurred on deleting item. "+e.getMessage();
+			throw new Exception(error);
 
 		} catch (Exception e) {
 			workspaceLogger.error("Error in server Item remove", e);
-//			workspaceLogger.trace("Error in server Item remove " + e);
-			//GWT can't serialize all exceptions
-			throw new Exception(e.getMessage());
+			String error = ConstantsExplorer.SERVER_ERROR +" deleting item. "+e.getMessage();
+			throw new Exception(error);
 		}
 
 	}
@@ -329,8 +341,6 @@ public class GWTWorkspaceServiceImpl extends RemoteServiceServlet implements GWT
 
 		} catch (Exception e) {
 			workspaceLogger.error("Error in server Item rename", e);
-//			workspaceLogger.trace("Error in server Item rename " + e);
-			//GWT can't serialize all exceptions
 			throw new Exception(e.getMessage());
 		}
 
@@ -1265,12 +1275,14 @@ public class GWTWorkspaceServiceImpl extends RemoteServiceServlet implements GWT
 				return true;
 			
 			return false;
+		}catch (InsufficientPrivilegesException e) {
+			String error = "An error occurred on copying item "  +e.getMessage() + ". "+ConstantsExplorer.TRY_AGAIN;
+			throw new Exception(error);
 
 		} catch (Exception e) {
 			workspaceLogger.error("Error in server copyItem  by id", e);
-//			workspaceLogger.trace("Error in server copyItem by id " + e);
-
-			throw new Exception(e.getMessage());
+			String error  = ConstantsExplorer.SERVER_ERROR +" copying item "  + ConstantsExplorer.TRY_AGAIN;
+			throw new Exception(error);
 		}
 	}
 
@@ -1363,10 +1375,26 @@ public class GWTWorkspaceServiceImpl extends RemoteServiceServlet implements GWT
 				
 			return created;
 
+		} catch (InsufficientPrivilegesException e) {
+			workspaceLogger.error("Error in shareFolder ", e);
+			String error = "An error occurred on creating shared folder. "+ e.getMessage();
+			throw new Exception(error);
+			
+		} catch (ItemAlreadyExistException e) {
+			workspaceLogger.error("Error in shareFolder ", e);
+			String error = "An error occurred on creating shared folder. "+ e.getMessage();
+			throw new Exception(error);
+			
+		} catch (WrongDestinationException e) {
+			workspaceLogger.error("Error in shareFolder ", e);
+			String error = "An error occurred on creating shared folder. "+ e.getMessage();
+			throw new Exception(error);
+
 		} catch (Exception e) {
 			workspaceLogger.error("Error in shareFolder ", e);
 			e.printStackTrace();
-			throw new Exception(e.getMessage());
+			String error = ConstantsExplorer.SERVER_ERROR+" creating shared folder. "+ e.getMessage();
+			throw new Exception(error);
 		}
 	}
 
@@ -1442,10 +1470,16 @@ public class GWTWorkspaceServiceImpl extends RemoteServiceServlet implements GWT
 			else
 				workspaceLogger.trace("the item with id: "+folderSharedId+ "is not  "+WorkspaceItemType.SHARED_FOLDER);
 			
+		} catch (InsufficientPrivilegesException e) {
+			workspaceLogger.error("Error in unSharedFolderByFolderSharedId ", e);
+			String error = "An error occerred on unsharing folder. "+ e.getMessage();
+			throw new Exception(error);
+			
 		} catch (Exception e) {
 			workspaceLogger.error("Error in unSharedFolderByFolderSharedId ", e);
+			String error = ConstantsExplorer.SERVER_ERROR+" un share folder. "+ e.getMessage() +". " +ConstantsExplorer.TRY_AGAIN;
 			e.printStackTrace();
-			throw new Exception(e.getMessage());
+			throw new Exception(error);
 		}
 		
 		return unShared;