diff --git a/src/main/java/org/olat/core/gui/components/table/DefaultXlsTableExporter.java b/src/main/java/org/olat/core/gui/components/table/DefaultXlsTableExporter.java
index 64c044f99407de9da0fa673c2818cc4a3920b06c..dca25e41bb303fb8e3b8a0a6e2b2f08707477ceb 100644
--- a/src/main/java/org/olat/core/gui/components/table/DefaultXlsTableExporter.java
+++ b/src/main/java/org/olat/core/gui/components/table/DefaultXlsTableExporter.java
@@ -36,6 +36,7 @@ import org.apache.poi.ss.usermodel.Font;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.util.WorkbookUtil;
 import org.olat.core.gui.media.CleanupAfterDeliveryFileMediaResource;
 import org.olat.core.gui.media.MediaResource;
 import org.olat.core.gui.render.StringOutput;
@@ -71,7 +72,8 @@ public class DefaultXlsTableExporter implements TableExporter {
 		headerCellStyle = getHeaderCellStyle(wb);
 		
 		String tableExportTitle = translator.translate("table.export.title");
-		Sheet exportSheet = wb.createSheet(tableExportTitle);
+		String saveTitle = WorkbookUtil.createSafeSheetName(tableExportTitle);
+		Sheet exportSheet = wb.createSheet(saveTitle);
 		createHeader(table, translator, cdcnt, exportSheet);
 		createData(table, cdcnt, rcnt, exportSheet);
 		
diff --git a/src/main/java/org/olat/course/db/CustomDBController.java b/src/main/java/org/olat/course/db/CustomDBController.java
index f108b007b17b5ddf3e6194dab9c2f61ee3bc288b..177293d447fc6d7434b3a84f927ce53bd8a0f8d6 100644
--- a/src/main/java/org/olat/course/db/CustomDBController.java
+++ b/src/main/java/org/olat/course/db/CustomDBController.java
@@ -32,6 +32,7 @@ import org.apache.poi.ss.usermodel.Font;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.util.WorkbookUtil;
 import org.olat.core.CoreSpringFactory;
 import org.olat.core.gui.UserRequest;
 import org.olat.core.gui.components.form.flexible.FormItem;
@@ -264,7 +265,8 @@ public class CustomDBController extends FormBasicController {
 
 		Workbook wb = new HSSFWorkbook();
 		CellStyle headerCellStyle = getHeaderCellStyle(wb);
-		Sheet exportSheet = wb.createSheet(courseTitle);
+		String saveTitle = WorkbookUtil.createSafeSheetName(courseTitle);
+		Sheet exportSheet = wb.createSheet(saveTitle);
 		
 		//create the headers
 		Row headerRow = exportSheet.createRow(0);
diff --git a/src/main/java/org/olat/instantMessaging/manager/ChatLogHelper.java b/src/main/java/org/olat/instantMessaging/manager/ChatLogHelper.java
index f529a98d040c1ae22628347c77f0eb6b0acd870a..df1157352f2584142c196594c689febbbff96afb 100644
--- a/src/main/java/org/olat/instantMessaging/manager/ChatLogHelper.java
+++ b/src/main/java/org/olat/instantMessaging/manager/ChatLogHelper.java
@@ -38,6 +38,7 @@ import org.apache.poi.ss.usermodel.Font;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.util.WorkbookUtil;
 import org.olat.basesecurity.IdentityImpl;
 import org.olat.core.gui.media.MediaResource;
 import org.olat.core.gui.media.WorkbookMediaResource;
@@ -115,7 +116,8 @@ public class ChatLogHelper {
 
 		Workbook wb = new HSSFWorkbook();
 		String tableExportTitle = translator.translate("logChat.export.title");
-		Sheet exportSheet = wb.createSheet(tableExportTitle);
+		String saveTitle = WorkbookUtil.createSafeSheetName(tableExportTitle);
+		Sheet exportSheet = wb.createSheet(saveTitle);
 		Formatter formatter = Formatter.getInstance(locale);
 		
 		//headers