diff --git a/src/Solver/RubarBE.py b/src/Solver/RubarBE.py
index dc43da93..ea5f21a1 100644
--- a/src/Solver/RubarBE.py
+++ b/src/Solver/RubarBE.py
@@ -170,7 +170,8 @@ class Rubar3(CommandLineSolver):
             hydraulics = self._hydraulic_data(study, values)
             geometry = self._geometry_data(hydraulics["edge"], trased)
             solid = self._solid_boundary(
-                study.river, hydraulics["edge"], values, trased)
+                study.river, hydraulics["edge"], values, trased,
+                hydraulics["warnings"])
             saves = self._save_data(values, hydraulics)
         except RubarExportError as error:
             self._cancel(qlog, str(error))
@@ -244,7 +245,7 @@ class Rubar3(CommandLineSolver):
                 reach=edge.name))
 
         warnings = []
-        boundaries = self._check_boundaries(river, edge, values)
+        boundaries = self._check_boundaries(river, edge, values, warnings)
 
         return {
             "edge": edge,
@@ -381,7 +382,7 @@ class Rubar3(CommandLineSolver):
             return float(old_pamhyr_date_to_timestamp(value))
         return float(value)
 
-    def _check_boundaries(self, river, edge, values):
+    def _check_boundaries(self, river, edge, values, warnings):
         """Liquid boundary conditions used for CONDAM, REGIME and CONDAV.
         Return {'hydro': bc, 'condav': bc} (or None)"""
         trad = RunSolverTranslate()
@@ -417,12 +418,12 @@ class Rubar3(CommandLineSolver):
 
         upstream = self._select_boundaries(
             at(edge.node1), self._upstream_types[condam], edge.node1,
-            {"TD": f"CONDAM={condam}"}, f"CONDAM={condam}"
+            {"TD": f"CONDAM={condam}"}, f"CONDAM={condam}", warnings
         )
         downstream = self._select_boundaries(
             at(edge.node2), self._downstream_types[condav], edge.node2,
             {"ZD": f"CONDAV={condav}", "TZ": f"CONDAV={condav}"},
-            f"CONDAV={condav}"
+            f"CONDAV={condav}", warnings
         )
 
         return {
@@ -430,9 +431,26 @@ class Rubar3(CommandLineSolver):
             "condav": downstream.get("ZD", downstream.get("TZ")),
         }
 
-    def _select_boundaries(self, bcs, expected, node, required_by, setting):
+    @staticmethod
+    def _ignore_empty(bcs, node, warnings):
+        """A boundary condition without value carries no data: it is
+        ignored with a warning. Return (kept, ignored)"""
+        trad = RunSolverTranslate()
+        kept, ignored = [], []
+        for bc in bcs:
+            if len(bc) == 0:
+                warnings.append(trad["boundary_empty_ignored"].format(
+                    name=bc.name, node=node.name))
+                ignored.append(bc)
+            else:
+                kept.append(bc)
+        return kept, ignored
+
+    def _select_boundaries(self, bcs, expected, node, required_by, setting,
+                           warnings):
         trad = RunSolverTranslate()
         selected = {}
+        bcs, ignored = self._ignore_empty(bcs, node, warnings)
 
         for bc in bcs:
             kind = self._boundary_kinds[bc.bctype]
@@ -443,9 +461,6 @@ class Rubar3(CommandLineSolver):
             if bc.bctype in selected:
                 raise RubarExportError(trad["boundary_ambiguous"].format(
                     kind=kind, node=node.name))
-            if len(bc) == 0:
-                raise RubarExportError(trad["boundary_empty"].format(
-                    name=bc.name, node=node.name))
             times = [d[0] for d in bc.data]
             if bc.bctype != "ZD" and any(
                     b < a for a, b in zip(times, times[1:])):
@@ -455,13 +470,19 @@ class Rubar3(CommandLineSolver):
 
         for bctype in expected:
             if bctype not in selected:
-                raise RubarExportError(trad["boundary_missing"].format(
+                message = trad["boundary_missing"].format(
                     setting=required_by[bctype],
-                    kind=self._boundary_kinds[bctype], node=node.name))
+                    kind=self._boundary_kinds[bctype], node=node.name)
+                # The required condition may be the ignored empty one
+                empty = [bc.name for bc in ignored if bc.bctype == bctype]
+                if empty:
+                    message += " " + trad["boundary_missing_empty"].format(
+                        names=", ".join(empty))
+                raise RubarExportError(message)
 
         return selected
 
-    def _solid_boundary(self, river, edge, values, trased):
+    def _solid_boundary(self, river, edge, values, trased, warnings):
         """Solid boundary condition written in HYDROS. RubarBE reads it
         at the upstream node when TRASED is enabled and CONDAM=1 (CONDAM=2
         is refused), and has no downstream solid condition (rubar_init.f90,
@@ -476,17 +497,19 @@ class Rubar3(CommandLineSolver):
             bc for bc in river.boundary_condition.get_tab("solid")
             if not bc.is_deleted() and bc.bctype == "SL"
         ]
-        for bc in solid:
-            if bc.node == edge.node2:
-                raise RubarExportError(
-                    trad["solid_boundary_downstream"].format(
-                        name=bc.name, node=edge.node2.name))
+        downstream, _ = self._ignore_empty(
+            [bc for bc in solid if bc.node == edge.node2], edge.node2,
+            warnings)
+        if downstream:
+            raise RubarExportError(
+                trad["solid_boundary_downstream"].format(
+                    name=downstream[0].name, node=edge.node2.name))
 
         expected = ("SL",) if condam == "1" else ()
         selected = self._select_boundaries(
             [bc for bc in solid if bc.node == edge.node1], expected,
             edge.node1, {"SL": f"TRASED=O, CONDAM={condam}"},
-            f"CONDAM={condam}"
+            f"CONDAM={condam}", warnings
         )
         bc = selected.get("SL")
         if bc is None:
diff --git a/src/View/RunSolver/Translate.py b/src/View/RunSolver/Translate.py
index c280fa33..e0f2902e 100644
--- a/src/View/RunSolver/Translate.py
+++ b/src/View/RunSolver/Translate.py
@@ -129,10 +129,14 @@ class RunSolverTranslate(PamhyrTranslate):
             "Export cancelled: several {kind} boundary conditions at node "
             "{node}."
         )
-        self._dict["boundary_empty"] = _translate(
+        self._dict["boundary_empty_ignored"] = _translate(
             "Solver",
-            "Export cancelled: boundary condition {name} at node {node} "
-            "has no value."
+            "Boundary condition {name} at node {node} has no value: it is "
+            "ignored."
+        )
+        self._dict["boundary_missing_empty"] = _translate(
+            "Solver",
+            "Empty boundary condition(s) ignored: {names}."
         )
         self._dict["boundary_not_sorted"] = _translate(
             "Solver",