diff --git a/api/wireguard_manager.py b/api/wireguard_manager.py
index 7a06789..abc5d12 100644
--- a/api/wireguard_manager.py
+++ b/api/wireguard_manager.py
@@ -216,7 +216,16 @@ class WireGuardManager(BaseServiceManager):
             return {'restarted': restarted, 'warnings': warnings}
         try:
             with open(cf) as f:
-                lines = f.readlines()
+                raw = f.read()
+
+            # Bootstrap from generate_config() if file is empty or has no [Interface]
+            if not raw.strip() or '[Interface]' not in raw:
+                raw = self.generate_config()
+                with open(cf, 'w') as f:
+                    f.write(raw)
+                warnings.append('wg0.conf was empty — regenerated from keys')
+
+            lines = raw.splitlines(keepends=True)
 
             def _set_iface_field(lines, key, value):
                 result = []