diff --git a/src/index/recollindex.cpp b/src/index/recollindex.cpp
index afd904a2..d2d179c5 100644
--- a/src/index/recollindex.cpp
+++ b/src/index/recollindex.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static char rcsid[] = "@(#$Id: recollindex.cpp,v 1.36 2008-08-29 09:51:24 dockes Exp $ (C) 2004 J.F.Dockes";
+static char rcsid[] = "@(#$Id: recollindex.cpp,v 1.37 2008-09-30 12:38:28 dockes Exp $ (C) 2004 J.F.Dockes";
 #endif
 /*
  *   This program is free software; you can redistribute it and/or modify
@@ -401,6 +401,9 @@ int main(int argc, const char **argv)
 
     } else {
 	confindexer = new ConfIndexer(config, &updater);
-	exit(!confindexer->index(rezero));
+	bool status = confindexer->index(rezero);
+	if (!status) 
+	    cerr << "Indexing failed" << endl;
+	exit(!status);
     }
 }
diff --git a/src/qtgui/confgui/confguiindex.cpp b/src/qtgui/confgui/confguiindex.cpp
index 694dffaa..3e5f73f5 100644
--- a/src/qtgui/confgui/confguiindex.cpp
+++ b/src/qtgui/confgui/confguiindex.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static char rcsid[] = "@(#$Id: confguiindex.cpp,v 1.12 2008-09-25 06:00:25 dockes Exp $ (C) 2007 J.F.Dockes";
+static char rcsid[] = "@(#$Id: confguiindex.cpp,v 1.13 2008-09-30 12:38:29 dockes Exp $ (C) 2007 J.F.Dockes";
 #endif
 
 #include <qglobal.h>
@@ -98,7 +98,7 @@ void ConfIndexW::acceptChanges()
     QTimer::singleShot(0, this, SLOT(reloadPanels()));
     if (startIndexingAfterConfig) {
 	startIndexingAfterConfig = 0;
-	startindexing = 1;
+	start_indexing(true);
     }
 }
 
diff --git a/src/qtgui/idxthread.cpp b/src/qtgui/idxthread.cpp
index 5b8afe49..f3b231c7 100644
--- a/src/qtgui/idxthread.cpp
+++ b/src/qtgui/idxthread.cpp
@@ -27,10 +27,11 @@
 #include "smallut.h"
 #include "rclinit.h"
 
-int stopindexing;
-int startindexing;
-IdxThreadStatus indexingstatus = IDXTS_OK;
-string indexingReason;
+static int stopindexing;
+static int startindexing;
+static bool rezero;
+static IdxThreadStatus indexingstatus = IDXTS_OK;
+static string indexingReason;
 static int stopidxthread;
 
 static QMutex curfile_mutex;
@@ -74,13 +75,14 @@ void IdxThread::run()
 	    myconf->getConfParam("loglevel", &loglevel);
 	    DebugLog::getdbl()->setloglevel(loglevel);
 	    ConfIndexer *indexer = new ConfIndexer(myconf, this);
-	    if (indexer->index()) {
+	    if (indexer->index(rezero)) {
 		indexingstatus = IDXTS_OK;
 		indexingReason = "";
 	    } else {
 		indexingstatus = IDXTS_ERROR;
 		indexingReason = "Indexing failed: " + indexer->getReason();
 	    }
+	    rezero = false;
 	    delete indexer;
 	} 
 	msleep(100);
@@ -101,7 +103,15 @@ void stop_idxthread()
     stopidxthread = 1;
     idxthread.wait();
 }
-
+void stop_indexing()
+{
+    stopindexing = 1;
+}
+void start_indexing(bool raz)
+{
+    startindexing = 1;
+    rezero = raz;
+}
 DbIxStatus idxthread_idxStatus()
 {
     QMutexLocker locker(&curfile_mutex);
@@ -111,3 +121,11 @@ bool idxthread_idxInterrupted()
 {
     return idxthread.m_interrupted;
 }
+string idxthread_getReason()
+{
+    return indexingReason;
+}
+IdxThreadStatus idxthread_getStatus()
+{
+    return indexingstatus;
+}
diff --git a/src/qtgui/idxthread.h b/src/qtgui/idxthread.h
index ec290d0f..1e5b4390 100644
--- a/src/qtgui/idxthread.h
+++ b/src/qtgui/idxthread.h
@@ -16,7 +16,7 @@
  */
 #ifndef _IDXTHREAD_H_INCLUDED_
 #define _IDXTHREAD_H_INCLUDED_
-/* @(#$Id: idxthread.h,v 1.7 2008-01-17 11:15:43 dockes Exp $  (C) 2004 J.F.Dockes */
+/* @(#$Id: idxthread.h,v 1.8 2008-09-30 12:38:29 dockes Exp $  (C) 2004 J.F.Dockes */
 #include <string>
 #include "indexer.h"
 
@@ -27,15 +27,16 @@ class RclConfig;
 extern void start_idxthread(const RclConfig& cnf);
 extern void stop_idxthread();
 
-// Set these to to request action
-extern int stopindexing;
-extern int startindexing;
+// Use these to to request action from thread
+extern void start_indexing(bool rezero = false);
+extern void stop_indexing();
 
-// indexingstatus is NULL iff indexing is currently in progress.
+// Final status of indexing. indexingstatus is NULL iff indexing is
+// currently in progress.
 enum IdxThreadStatus {IDXTS_NULL = 0, IDXTS_OK = 1, IDXTS_ERROR = 2};
-extern IdxThreadStatus indexingstatus;
-// Final indexing status message
-extern string indexingReason;
+extern IdxThreadStatus idxthread_getStatus();
+extern string idxthread_getReason();
+
 // Current status of running indexing (phase, file name etc.)
 extern DbIxStatus idxthread_idxStatus();
 // Did last op fail because of stop request ?
diff --git a/src/qtgui/main.cpp b/src/qtgui/main.cpp
index 81217fbd..cec336ab 100644
--- a/src/qtgui/main.cpp
+++ b/src/qtgui/main.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static char rcsid[] = "@(#$Id: main.cpp,v 1.69 2008-09-24 05:35:03 dockes Exp $ (C) 2005 J.F.Dockes";
+static char rcsid[] = "@(#$Id: main.cpp,v 1.70 2008-09-30 12:38:29 dockes Exp $ (C) 2005 J.F.Dockes";
 #endif
 /*
  *   This program is free software; you can redistribute it and/or modify
@@ -338,12 +338,11 @@ int main(int argc, char **argv)
 		 "Ok", "Cancel", 0,   0)) {
 
 	case 0: // Ok: indexing is going to start.
-	    startindexing = 1;
+	    start_indexing(true);
 	    break;
 
 	case 1: // Cancel
 	    needindexconfig = true;
-	    startindexing = 0;
 	    break;
 	}
     }
diff --git a/src/qtgui/rclmain_w.cpp b/src/qtgui/rclmain_w.cpp
index 9197b836..ec80a691 100644
--- a/src/qtgui/rclmain_w.cpp
+++ b/src/qtgui/rclmain_w.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static char rcsid[] = "@(#$Id: rclmain_w.cpp,v 1.54 2008-09-29 11:33:55 dockes Exp $ (C) 2005 J.F.Dockes";
+static char rcsid[] = "@(#$Id: rclmain_w.cpp,v 1.55 2008-09-30 12:38:29 dockes Exp $ (C) 2005 J.F.Dockes";
 #endif
 /*
  *   This program is free software; you can redistribute it and/or modify
@@ -358,20 +358,20 @@ void RclMain::periodic100()
 {
     static int toggle = 0;
     // Check if indexing thread done
-    if (indexingstatus != IDXTS_NULL) {
+    if (idxthread_getStatus() != IDXTS_NULL) {
 	// Indexing is stopped
 	statusBar()->message("");
 	fileToggleIndexingAction->setText(tr("Update &Index"));
 	fileToggleIndexingAction->setEnabled(TRUE);
 	if (m_idxStatusAck == false) {
 	    m_idxStatusAck = true;
-	    if (indexingstatus != IDXTS_OK) {
+	    if (idxthread_getStatus() != IDXTS_OK) {
 		if (idxthread_idxInterrupted()) {
 		    QMessageBox::warning(0, "Recoll", 
 					 tr("Indexing interrupted"));
 		} else {
 		    QMessageBox::warning(0, "Recoll", 
-					 QString::fromAscii(indexingReason.c_str()));
+		       QString::fromAscii(idxthread_getReason().c_str()));
 		}
 	    }
 	    // Make sure we reopen the db to get the results. If there
@@ -427,12 +427,12 @@ void RclMain::periodic100()
 
 void RclMain::toggleIndexing()
 {
-    if (indexingstatus == IDXTS_NULL) {
+    if (idxthread_getStatus() == IDXTS_NULL) {
 	// Indexing in progress
-	stopindexing = 1;
+	stop_indexing();
 	fileToggleIndexingAction->setText(tr("Update &Index"));
     } else {
-	startindexing = 1;
+	start_indexing(false);
 	fileToggleIndexingAction->setText(tr("Stop &Indexing"));
     }
     fileToggleIndexingAction->setEnabled(FALSE);
@@ -448,11 +448,11 @@ static string urltolocalpath(string url)
 void RclMain::startSearch(RefCntr<Rcl::SearchData> sdata)
 {
     LOGDEB(("RclMain::startSearch. Indexing %s\n", 
-	    indexingstatus == IDXTS_NULL?"on":"off"));
+	    idxthread_getStatus() == IDXTS_NULL?"on":"off"));
     // The db may have been closed at the end of indexing
     string reason;
     // If indexing is being performed, we reopen the db at each query.
-    if (!maybeOpenDb(reason, indexingstatus == IDXTS_NULL)) {
+    if (!maybeOpenDb(reason, idxthread_getStatus() == IDXTS_NULL)) {
 	QMessageBox::critical(0, "Recoll", QString(reason.c_str()));
 	return;
     }
diff --git a/src/rcldb/rcldb.cpp b/src/rcldb/rcldb.cpp
index e17183c2..f3291779 100644
--- a/src/rcldb/rcldb.cpp
+++ b/src/rcldb/rcldb.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static char rcsid[] = "@(#$Id: rcldb.cpp,v 1.146 2008-09-29 08:59:20 dockes Exp $ (C) 2004 J.F.Dockes";
+static char rcsid[] = "@(#$Id: rcldb.cpp,v 1.147 2008-09-30 12:38:29 dockes Exp $ (C) 2004 J.F.Dockes";
 #endif
 /*
  *   This program is free software; you can redistribute it and/or modify
@@ -67,6 +67,10 @@ enum value_slot {
     VALUE_SIG = 10      // Doc sig as chosen by app (ex: mtime+size
 };
 
+// Recoll index format version is stored in user metadata. When this change,
+// we can't open the db and will have to reindex.
+static const string RCL_IDX_VERSION_KEY("RCL_IDX_VERSION_KEY");
+static const string RCL_IDX_VERSION("1");
 
 // This is the word position offset at which we index the body text
 // (abstract, keywords, etc.. are stored before this)
@@ -514,10 +518,11 @@ bool Db::open(const string& dir, const string &stops, OpenMode mode,
 		    Xapian::DB_CREATE_OR_OVERWRITE;
 		m_ndb->wdb = Xapian::WritableDatabase(dir, action);
 		m_ndb->m_iswritable = true;
-		// We open a readonly object in addition to the r/w
-		// one because some operations are faster when
-		// performed through a Database (no forced flushes on
-		// allterms_begin(), ie, used in subDocs()
+		// We open a readonly object in all cases (possibly in
+		// addition to the r/w one) because some operations
+		// are faster when performed through a Database: no
+		// forced flushes on allterms_begin(), ie, used in
+		// subDocs()
 		m_ndb->db = Xapian::Database(dir);
 		LOGDEB(("Db::open: lastdocid: %d\n", 
 			m_ndb->wdb.get_lastdocid()));
@@ -548,6 +553,19 @@ bool Db::open(const string& dir, const string &stops, OpenMode mode,
 	    }
 	    break;
 	}
+	// Check index format version. Must not try to check a just created or
+	// truncated db
+	if (mode != DbTrunc && m_ndb->db.get_doccount()>0) {
+	    Xapian::Database cdb = m_ndb->m_iswritable ? m_ndb->wdb: m_ndb->db;
+	    string version = cdb.get_metadata(RCL_IDX_VERSION_KEY);
+	    if (version.compare(RCL_IDX_VERSION)) {
+		m_ndb->m_noversionwrite = true;
+		LOGERR(("Rcl::Db::open: file index [%s], software [%s]\n",
+			version.c_str(), RCL_IDX_VERSION.c_str()));
+		throw Xapian::DatabaseError("Recoll index version mismatch",
+					    "", "");
+	    }
+	}
 	m_mode = mode;
 	m_ndb->m_isopen = true;
 	m_basedir = dir;
@@ -577,8 +595,11 @@ bool Db::i_close(bool final)
     string ermsg;
     try {
 	bool w = m_ndb->m_iswritable;
-	if (w)
+	if (w) {
+	    if (!m_ndb->m_noversionwrite)
+		m_ndb->wdb.set_metadata(RCL_IDX_VERSION_KEY, RCL_IDX_VERSION);
 	    LOGDEB(("Rcl::Db:close: xapian will close. May take some time\n"));
+	}
 	// Used to do a flush here. Cant see why it should be necessary.
 	deleteZ(m_ndb);
 	if (w)
diff --git a/src/rcldb/rcldb_p.h b/src/rcldb/rcldb_p.h
index bf73915d..c2db458d 100644
--- a/src/rcldb/rcldb_p.h
+++ b/src/rcldb/rcldb_p.h
@@ -4,7 +4,7 @@
 #include "xapian.h"
 
 namespace Rcl {
-/* @(#$Id: rcldb_p.h,v 1.5 2008-09-16 08:18:30 dockes Exp $  (C) 2007 J.F.Dockes */
+/* @(#$Id: rcldb_p.h,v 1.6 2008-09-30 12:38:29 dockes Exp $  (C) 2007 J.F.Dockes */
 
 // Generic Xapian exception catching code. We do this quite often,
 // and I have no idea how to do this except for a macro
@@ -30,10 +30,10 @@ class Query;
 // common.
 class Db::Native {
  public:
-    Db *m_db;
+    Db  *m_db;
     bool m_isopen;
     bool m_iswritable;
-
+    bool m_noversionwrite; //Set if open failed because of version mismatch!
     // Indexing
     Xapian::WritableDatabase wdb;
 
@@ -41,7 +41,7 @@ class Db::Native {
     Xapian::Database db;
     
     Native(Db *db) 
-	: m_db(db), m_isopen(false), m_iswritable(false)
+	: m_db(db), m_isopen(false), m_iswritable(false),m_noversionwrite(false)
     { }
 
     ~Native() {