diff --git a/src/backend/datasources/filters/AbstractFileFilter.cpp b/src/backend/datasources/filters/AbstractFileFilter.cpp
index 050bb5242..76e28f887 100644
--- a/src/backend/datasources/filters/AbstractFileFilter.cpp
+++ b/src/backend/datasources/filters/AbstractFileFilter.cpp
@@ -1,79 +1,82 @@
 /***************************************************************************
 File                 : AbstractFileFilter.h
 Project              : LabPlot
 Description          : file I/O-filter related interface
 --------------------------------------------------------------------
 Copyright            : (C) 2009-2017 Alexander Semke (alexander.semke@web.de)
 Copyright            : (C) 2017 Stefan Gerlach (stefan.gerlach@uni.kn)
 ***************************************************************************/
 
 /***************************************************************************
  *                                                                         *
  *  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                                           *
  *                                                                         *
  ***************************************************************************/
 
 #include "backend/datasources/filters/AbstractFileFilter.h"
 #include "backend/lib/macros.h"
 #include <QDateTime>
 #include <QLocale>
 #include <KLocale>
 
 bool AbstractFileFilter::isNan(QString s) {
 	QStringList nanStrings;
 	nanStrings << "NA" << "NAN" << "N/A" << "-NA" << "-NAN" << "NULL";
 	if (nanStrings.contains(s, Qt::CaseInsensitive))
 		return true;
 
 	return false;
 }
 
 AbstractColumn::ColumnMode AbstractFileFilter::columnMode(const QString& valueString, const QString& dateTimeFormat, QLocale::Language lang) {
 	QLocale locale(lang);
 
+	if (valueString.size() == 0)	// empty string treated as integer (meaning the non-empty strings will determine the data type)
+		return AbstractColumn::Integer;
+
 	// check if integer first
 	bool ok;
 	locale.toInt(valueString, &ok);
 	DEBUG("string " << valueString.toStdString() << ": toInt " << locale.toInt(valueString, &ok) << "?:" << ok);
 	if (ok || isNan(valueString))
 		return AbstractColumn::Integer;
 
 	//try to convert to a double
 	AbstractColumn::ColumnMode mode = AbstractColumn::Numeric;
 	locale.toDouble(valueString, &ok);
 
 	//if not a number, check datetime. if that fails: string
 	if (!ok) {
 		QDateTime valueDateTime = QDateTime::fromString(valueString, dateTimeFormat);
 		if (valueDateTime.isValid())
 			mode = AbstractColumn::DateTime;
 		else
 			mode = AbstractColumn::Text;
 	}
 
 	return mode;
 }
 
 /*
 returns the list of all supported locales for numeric data
 */
 QStringList AbstractFileFilter::numberFormats() {
 	QStringList formats;
 	for (int l = 0; l < ENUM_COUNT(QLocale, Language); ++l)
 		formats << QLocale::languageToString((QLocale::Language)l);
 
 	return formats;
 }