diff --git a/cle/backends/coff.py b/cle/backends/coff.py
index fc945d28..fb8af4fc 100644
--- a/cle/backends/coff.py
+++ b/cle/backends/coff.py
@@ -445,6 +445,8 @@ def __init__(self, *args, **kwargs):
         self.memory.add_backer(0, bytes(self._image_vmem))
         self.mapped_base = self.linked_base = 0
         self.pic = True
+        # assume windows, this can be wrong, but is more often right.
+        self.os = "windows"
 
         self._add_defined_symbols()
         self._add_relocs()