diff --git a/xmake/rules/qt/load.lua b/xmake/rules/qt/load.lua
index 593a541d95c..070ae2c0d3f 100644
--- a/xmake/rules/qt/load.lua
+++ b/xmake/rules/qt/load.lua
@@ -482,10 +482,12 @@ function main(target, opt)
             target:add("defines", "_WINDOWS")
             local subsystem = false
             for _, ldflag in ipairs(target:get("ldflags")) do
-                ldflag = ldflag:lower()
-                if ldflag:find("[/%-]subsystem:") then
-                    subsystem = true
-                    break
+                if type(ldflag) == "string" then
+                    ldflag = ldflag:lower()
+                    if ldflag:find("[/%-]subsystem:") then
+                        subsystem = true
+                        break
+                    end
                 end
             end
             -- maybe user will set subsystem to console
diff --git a/xmake/rules/wdk/load.lua b/xmake/rules/wdk/load.lua
index d309dbb4efe..62cf99467a1 100644
--- a/xmake/rules/wdk/load.lua
+++ b/xmake/rules/wdk/load.lua
@@ -79,10 +79,12 @@ function driver_kmdf(target)
     -- set default driver entry if does not exist
     local entry = false
     for _, ldflag in ipairs(target:get("ldflags")) do
-        ldflag = ldflag:lower()
-        if ldflag:find("[/%-]entry:") then
-            entry = true
-            break
+        if type(ldflag) == "string" then
+            ldflag = ldflag:lower()
+            if ldflag:find("[/%-]entry:") then
+                entry = true
+                break
+            end
         end
     end
     if not entry then
@@ -120,10 +122,12 @@ function driver_wdm(target)
     -- set default driver entry if does not exist
     local entry = false
     for _, ldflag in ipairs(target:get("ldflags")) do
-        ldflag = ldflag:lower()
-        if ldflag:find("[/%-]entry:") then
-            entry = true
-            break
+        if type(ldflag) == "string" then
+            ldflag = ldflag:lower()
+            if ldflag:find("[/%-]entry:") then
+                entry = true
+                break
+            end
         end
     end
     if not entry then
diff --git a/xmake/rules/winsdk/xmake.lua b/xmake/rules/winsdk/xmake.lua
index 297dfda751b..b782c4f1fb5 100644
--- a/xmake/rules/winsdk/xmake.lua
+++ b/xmake/rules/winsdk/xmake.lua
@@ -40,10 +40,12 @@ rule("win.sdk.application")
         else
             local subsystem = false
             for _, ldflag in ipairs(target:get("ldflags")) do
-                ldflag = ldflag:lower()
-                if ldflag:find("[/%-]subsystem:") then
-                    subsystem = true
-                    break
+                if type(ldflag) == "string" then
+                    ldflag = ldflag:lower()
+                    if ldflag:find("[/%-]subsystem:") then
+                        subsystem = true
+                        break
+                    end
                 end
             end
             if not subsystem then