diff --git a/src/Mod/Assembly/App/AssemblyObject.cpp b/src/Mod/Assembly/App/AssemblyObject.cpp
index 6902acd44b..a8c498cffa 100644
--- a/src/Mod/Assembly/App/AssemblyObject.cpp
+++ b/src/Mod/Assembly/App/AssemblyObject.cpp
@@ -275,8 +275,14 @@ void AssemblyObject::updateSolveStatus()
     //+1 because there's a grounded joint to origin
     lastDoF = (1 + numberOfComponents()) * 6;
 
-    if (!solver_ || lastResult_.placements.empty()) {
+    // Guard against re-entrancy: solve() calls updateSolveStatus(), so if
+    // placements are legitimately empty (e.g. zero constraints / all parts
+    // grounded) the recursive solve() would never terminate.
+    static bool updating = false;
+    if (!updating && (!solver_ || lastResult_.placements.empty())) {
+        updating = true;
         solve();
+        updating = false;
     }
 
     if (!solver_) {