diff --git a/os/osx/dnd.mm b/os/osx/dnd.mm
index f65afae33..f7e6b4a38 100644
--- a/os/osx/dnd.mm
+++ b/os/osx/dnd.mm
@@ -72,7 +72,7 @@
 
 NSDragOperation as_nsdragoperation(const os::DropOperation op)
 {
-  NSDragOperation nsdop;
+  NSDragOperation nsdop = NSDragOperationNone;
   if (static_cast<int>(op) & static_cast<int>(os::DropOperation::Copy))
     nsdop |= NSDragOperationCopy;
 
@@ -87,7 +87,7 @@ NSDragOperation as_nsdragoperation(const os::DropOperation op)
 
 os::DropOperation as_dropoperation(const NSDragOperation nsdop)
 {
-  int op = 0;
+  int op = static_cast<int>(os::DropOperation::None);
   if (nsdop & NSDragOperationCopy)
     op |= static_cast<int>(os::DropOperation::Copy);
 
diff --git a/os/win/dnd.cpp b/os/win/dnd.cpp
index 4f3b8002f..5af81407e 100644
--- a/os/win/dnd.cpp
+++ b/os/win/dnd.cpp
@@ -33,7 +33,7 @@ DWORD as_dropeffect(const os::DropOperation op)
 
 os::DropOperation as_dropoperation(DWORD pdwEffect)
 {
-  int op = 0;
+  int op = static_cast<int>(os::DropOperation::None);
   if (pdwEffect & DROPEFFECT_COPY)
     op |= static_cast<int>(os::DropOperation::Copy);