diff --git a/src/json/cmdhelper.cpp b/src/json/cmdhelper.cpp
index aba41a5..69b1b6c 100644
--- a/src/json/cmdhelper.cpp
+++ b/src/json/cmdhelper.cpp
@@ -62,6 +62,7 @@ bool cmdHelper::getDiskUsed(double& used)
 	{
 		QString qstr = QString::fromStdString(str);
 		QStringList strList = qstr.split('\n');
+		if (strList.length()<3) return false;
 		strList[1].replace(QRegExp("[\\s]+"), " ");
 		QStringList strList2 = strList[1].split(" ");
 		int pos = strList2[2].lastIndexOf(QChar('G'));