diff --git a/lib/core/common.py b/lib/core/common.py
index df22dd4f52b..ca9dd97f1aa 100755
--- a/lib/core/common.py
+++ b/lib/core/common.py
@@ -2215,16 +2215,16 @@ def urlencode(value, safe="%&=-_", convall=False, limit=False, spaceplus=False):
     if conf.get("direct"):
         return value
 
-    if Backend.isDbms(DBMS.MSSQL) and not kb.tamperFunctions and any(ord(_) > 255 for _ in value):
-        warnMsg = "if you experience problems with "
-        warnMsg += "non-ASCII identifier names "
-        warnMsg += "you are advised to rerun with '--tamper=charunicodeencode'"
-        singleTimeWarnMessage(warnMsg)
-
     count = 0
     result = None if value is None else ""
 
     if value:
+        if Backend.isDbms(DBMS.MSSQL) and not kb.tamperFunctions and any(ord(_) > 255 for _ in value):
+            warnMsg = "if you experience problems with "
+            warnMsg += "non-ASCII identifier names "
+            warnMsg += "you are advised to rerun with '--tamper=charunicodeencode'"
+            singleTimeWarnMessage(warnMsg)
+
         if convall or safe is None:
             safe = ""