diff --git a/src/java/davmail/exception/WebdavNotAvailableException.java b/src/java/davmail/exception/WebdavNotAvailableException.java
new file mode 100644
index 00000000..fabd8209
--- /dev/null
+++ b/src/java/davmail/exception/WebdavNotAvailableException.java
@@ -0,0 +1,34 @@
+/*
+ * DavMail POP/IMAP/SMTP/CalDav/LDAP Exchange Gateway
+ * Copyright (C) 2010  Mickael Guessant
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package davmail.exception;
+
+/**
+ * Exchange 2007 with Webdav disabled will trigger this exception.
+ */
+public class WebdavNotAvailableException extends DavMailException {
+    /**
+     * Create a DavMail exception with the given BundleMessage key and arguments.
+     *
+     * @param key       message key
+     * @param arguments message values
+     */
+    public WebdavNotAvailableException(String key, Object... arguments) {
+        super(key, arguments);
+    }
+}
diff --git a/src/java/davmail/exchange/ExchangeSessionFactory.java b/src/java/davmail/exchange/ExchangeSessionFactory.java
index 74628f21..1d2870c6 100644
--- a/src/java/davmail/exchange/ExchangeSessionFactory.java
+++ b/src/java/davmail/exchange/ExchangeSessionFactory.java
@@ -22,6 +22,7 @@ import davmail.BundleMessage;
 import davmail.Settings;
 import davmail.exception.DavMailAuthenticationException;
 import davmail.exception.DavMailException;
+import davmail.exception.WebdavNotAvailableException;
 import davmail.exchange.dav.DavExchangeSession;
 import davmail.exchange.ews.EwsExchangeSession;
 import davmail.http.DavGatewayHttpClientFacade;
@@ -114,7 +115,16 @@ public final class ExchangeSessionFactory {
                 if (Settings.getBooleanProperty("davmail.enableEws")) {
                     session = new EwsExchangeSession(poolKey.url, poolKey.userName, poolKey.password);
                 } else {
-                    session = new DavExchangeSession(poolKey.url, poolKey.userName, poolKey.password);
+                    try {
+                        session = new DavExchangeSession(poolKey.url, poolKey.userName, poolKey.password);
+                    } catch (WebdavNotAvailableException e) {
+                        ExchangeSession.LOGGER.debug(e.getMessage()+", retry with EWS");
+                        session = new EwsExchangeSession(poolKey.url, poolKey.userName, poolKey.password);
+                        // success, enable EWS flag
+                        ExchangeSession.LOGGER.debug("EWS found, changing davmail.enableEws setting");
+                        Settings.setProperty("davmail.enableEws", "true");
+                        Settings.save();
+                    }
                 }
                 ExchangeSession.LOGGER.debug("Created new session: " + session);
             }
diff --git a/src/java/davmail/exchange/dav/DavExchangeSession.java b/src/java/davmail/exchange/dav/DavExchangeSession.java
index 590383e8..37d01f27 100644
--- a/src/java/davmail/exchange/dav/DavExchangeSession.java
+++ b/src/java/davmail/exchange/dav/DavExchangeSession.java
@@ -662,7 +662,7 @@ public class DavExchangeSession extends ExchangeSession {
             responses = DavGatewayHttpClientFacade.executePropFindMethod(
                     httpClient, URIUtil.encodePath(mailPath), 0, WELL_KNOWN_FOLDERS);
             if (responses.length == 0) {
-                throw new DavMailException("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath);
+                throw new WebdavNotAvailableException("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath);
             }
             DavPropertySet properties = responses[0].getProperties(HttpStatus.SC_OK);
             inboxUrl = getURIPropertyIfExists(properties, "inbox");
@@ -728,7 +728,7 @@ public class DavExchangeSession extends ExchangeSession {
             );
         } catch (IOException e) {
             LOGGER.error(e.getMessage());
-            throw new DavMailAuthenticationException("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath);
+            throw new WebdavNotAvailableException("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath);
         }
     }