diff --git a/gns3server/controller/symbols.py b/gns3server/controller/symbols.py
index 671a9fbc..ab59d27d 100644
--- a/gns3server/controller/symbols.py
+++ b/gns3server/controller/symbols.py
@@ -66,7 +66,7 @@ class Symbols:
                 for filename in files:
                     if filename.startswith('.'):
                         continue
-                    symbol_file = posixpath.normpath(os.path.relpath(os.path.join(root, filename), get_resource("symbols")))
+                    symbol_file = posixpath.normpath(os.path.relpath(os.path.join(root, filename), get_resource("symbols"))).replace('\\', '/')
                     symbol_id = ':/symbols/' + symbol_file
                     symbols.append({'symbol_id': symbol_id,
                                     'filename': symbol_file,
@@ -79,7 +79,7 @@ class Symbols:
                 for filename in files:
                     if filename.startswith('.'):
                         continue
-                    symbol_file = posixpath.normpath(os.path.relpath(os.path.join(root, filename), directory))
+                    symbol_file = posixpath.normpath(os.path.relpath(os.path.join(root, filename), directory)).replace('\\', '/')
                     symbols.append({'symbol_id': symbol_file,
                                     'filename': symbol_file,
                                     'builtin': False,})