diff --git a/sohstationviewer/view/main_window.py b/sohstationviewer/view/main_window.py
index ac29e1ffa03fa3f839dbb441332f6c1a740a1e72..f9369b556596902dd662a0e094959a4e1d2d1741 100755
--- a/sohstationviewer/view/main_window.py
+++ b/sohstationviewer/view/main_window.py
@@ -540,11 +540,14 @@ class MainWindow(QtWidgets.QMainWindow, UIMainWindow):
         else:
             self.min_gap = None
 
-        try:
-            check_chan_wildcards_format(self.mseed_wildcard_edit.text())
-        except Exception as e:
-            QtWidgets.QMessageBox.warning(self, "Incorrect Wildcard", str(e))
-            return
+        if self.mseed_wildcard_edit.text().strip() != '':
+            try:
+                check_chan_wildcards_format(self.mseed_wildcard_edit.text())
+            except Exception as e:
+                QtWidgets.QMessageBox.warning(
+                    self, "Incorrect Wildcard", str(e))
+                return
+
         try:
             del self.data_object
             self.processing_log = []
diff --git a/sohstationviewer/view/util/functions.py b/sohstationviewer/view/util/functions.py
index 50332b76df62d2fbebdec88ace58430d1d766998..2927cae8c88a35dbe38423b4448c5c615c469da9 100644
--- a/sohstationviewer/view/util/functions.py
+++ b/sohstationviewer/view/util/functions.py
@@ -170,7 +170,7 @@ def check_chan_wildcards_format(wildcards: str):
     :param wildcards: wildcards that are separated with ','.
     :type wildcards: str
     """
-    for wc in wildcards.split():
+    for wc in wildcards.split(','):
         wc = wc.strip()
 
         if len(wc) == 1 and wc != '*':