diff --git a/dom/clients/manager/ClientManagerService.cpp b/dom/clients/manager/ClientManagerService.cpp
index 9baf17f854a2..0390b4a9536f 100644
--- a/dom/clients/manager/ClientManagerService.cpp
+++ b/dom/clients/manager/ClientManagerService.cpp
@@ -167,6 +167,18 @@ void ClientManagerService::Shutdown() {
        CopyableAutoTArray<ClientManagerParent*, 16>(mManagerList)) {
     Unused << PClientManagerParent::Send__delete__(actor);
   }
+
+  // Destroying manager actors should've also destroyed all source actors, so
+  // the only sources left will be future sources, which need to be aborted.
+  for (auto& entry : mSourceTable) {
+    MOZ_RELEASE_ASSERT(entry.GetData().is<FutureClientSourceParent>());
+    CopyableErrorResult rv;
+    rv.ThrowInvalidStateError("Client creation aborted.");
+    entry.GetModifiableData()
+        ->as<FutureClientSourceParent>()
+        .RejectPromiseIfExists(rv);
+  }
+  mSourceTable.Clear();
 }
 
 ClientSourceParent* ClientManagerService::MaybeUnwrapAsExistingSource(