diff --git a/DSView/pv/data/decoderstack.cpp b/DSView/pv/data/decoderstack.cpp
index a2bf1658..1311363b 100644
--- a/DSView/pv/data/decoderstack.cpp
+++ b/DSView/pv/data/decoderstack.cpp
@@ -560,6 +560,11 @@ void DecoderStack::decode_data(const uint64_t decode_start, const uint64_t decod
 
                 uint64_t align_sample_count = _snapshot->get_ring_sample_count();
 
+                if (align_sample_count == 0){
+                    dsv_info("Have no data to decode.");
+                    return;
+                }
+
                 if (end_index >= align_sample_count){
                     end_index = align_sample_count - 1;
                     dsv_info("Reset the decode end sample, new:%llu, old:%llu", 
diff --git a/DSView/pv/sigsession.cpp b/DSView/pv/sigsession.cpp
index eb654c1a..02ef29af 100644
--- a/DSView/pv/sigsession.cpp
+++ b/DSView/pv/sigsession.cpp
@@ -1688,7 +1688,15 @@ namespace pv
     {
         auto trace = get_decoder_trace(index);
 
-        if (trace && trace->create_popup(false))
+        if (trace == NULL){
+            return;
+        }
+
+        if (!trace->create_popup(false)){
+            return;
+        }
+
+        if (have_view_data() && !is_working())
         {
             remove_decode_task(trace); // remove old task
             trace->decoder()->clear();
@@ -1868,8 +1876,7 @@ namespace pv
         std::lock_guard<std::mutex> lock(_decode_task_mutex);
         _decode_tasks.push_back(trace);
 
-        if (!_is_decoding)
-        {
+        if (!_is_decoding){
             if (_decode_thread.joinable())
                 _decode_thread.join();