diff --git a/DSView/pv/device/file.cpp b/DSView/pv/device/file.cpp
index 13f5d3cb..230d6f7a 100644
--- a/DSView/pv/device/file.cpp
+++ b/DSView/pv/device/file.cpp
@@ -28,6 +28,7 @@
 #include "../utility/path.h"
 #include <stdlib.h>
 #include "../ZipMaker.h"
+#include "../log.h"
 
 namespace pv {
 namespace device {
@@ -80,11 +81,18 @@ QJsonArray File::get_decoders()
     ZipReader rd(f_name.c_str());
     auto *data = rd.GetInnterFileData("decoders");
 
-    if (data != NULL){
-          QJsonDocument sessionDoc = QJsonDocument::fromJson(
-                                        QByteArray::fromRawData(data->data(), data->size()), &error);
-          dec_array = sessionDoc.array();
-          rd.ReleaseInnerFileData(data);
+    if (data != NULL){ 
+        QString jsonStr(data->data());
+        QByteArray qbs = jsonStr.toUtf8(); 
+        QJsonDocument sessionDoc = QJsonDocument::fromJson(qbs, &error);
+
+        if (error.error != QJsonParseError::NoError){
+            QString estr = error.errorString();
+            dsv_err("File::get_decoders(), parse json error:\"%s\"!", estr.toUtf8().data());
+        } 
+
+        dec_array = sessionDoc.array();
+        rd.ReleaseInnerFileData(data);
     }
  
     return dec_array;
@@ -100,8 +108,15 @@ QJsonDocument File::get_session()
     auto *data = rd.GetInnterFileData("session");
 
      if (data != NULL){
-          sessionDoc = QJsonDocument::fromJson(
-                                        QByteArray::fromRawData(data->data(), data->size()), &error);
+        QString jsonStr(data->data());
+        QByteArray qbs = jsonStr.toUtf8(); 
+        sessionDoc = QJsonDocument::fromJson(qbs, &error);
+
+        if (error.error != QJsonParseError::NoError){
+            QString estr = error.errorString();
+            dsv_err("File::get_session(), parse json error:\"%s\"!", estr.toUtf8().data());
+        } 
+
         rd.ReleaseInnerFileData(data);
     }
 
diff --git a/DSView/pv/sigsession.cpp b/DSView/pv/sigsession.cpp
index d866df82..e564fc15 100644
--- a/DSView/pv/sigsession.cpp
+++ b/DSView/pv/sigsession.cpp
@@ -1375,6 +1375,13 @@ uint16_t SigSession::get_ch_num(int type)
 bool SigSession::add_decoder(srd_decoder *const dec, bool silent, DecoderStatus *dstatus, 
         std::list<pv::data::decode::Decoder*> &sub_decoders){
 
+       if (dec == NULL){
+          dsv_err("%s", "Decoder instance is null!");
+          assert(false);
+       }
+
+       dsv_info("Create new decoder,name:\"%s\",id:\"%s\"", dec->name, dec->id);
+
       try { 
 
         bool ret = false;
diff --git a/DSView/pv/storesession.cpp b/DSView/pv/storesession.cpp
index 2c5caea0..fee12150 100644
--- a/DSView/pv/storesession.cpp
+++ b/DSView/pv/storesession.cpp
@@ -60,6 +60,7 @@
 #include "dsvdef.h"
 #include "utility/encoding.h"
 #include "utility/path.h"
+#include "log.h"
 
  
 namespace pv { 
@@ -951,7 +952,7 @@ bool StoreSession::json_decoders(QJsonArray &array)
         auto rows = stack->get_rows_gshow();
         for (auto i = rows.begin(); i != rows.end(); i++) {
             pv::data::decode::Row _row = (*i).first;
-            QString kn = _row.title();
+            QString kn(_row.title().toUtf8().data());
             show_obj[kn] = QJsonValue::fromVariant((*i).second);
         }
         dec_obj["show"] = show_obj;
@@ -964,8 +965,14 @@ bool StoreSession::json_decoders(QJsonArray &array)
 
 bool StoreSession::load_decoders(dock::ProtocolDock *widget, QJsonArray dec_array)
 {
-    if (_session->get_device()->dev_inst()->mode != LOGIC || dec_array.empty())
+    if (_session->get_device()->dev_inst()->mode != LOGIC)
     {
+        dsv_info("%s", "StoreSession::load_decoders(), is not LOGIC mode.");
+        return false;
+    }
+
+    if (dec_array.empty()){
+        dsv_info("%s", "StoreSession::load_decoders(), json object is array empty.");
         return false;
     }
     
@@ -1139,7 +1146,8 @@ bool StoreSession::load_decoders(dock::ProtocolDock *widget, QJsonArray dec_arra
                 std::map<const pv::data::decode::Row, bool> rows = stack->get_rows_gshow();
 
                 for (auto i = rows.begin();i != rows.end(); i++) {
-                        QString key = (*i).first.title();
+                    QString key = (*i).first.title();
+
                     if (show_obj.contains(key)) {
                         bool bShow = show_obj[key].toBool();
                         const pv::data::decode::Row r = (*i).first;