diff --git a/backend/src/workspaces/preprocessing-service.ts b/backend/src/workspaces/preprocessing-service.ts
index da5d7bc6..9afe0390 100644
--- a/backend/src/workspaces/preprocessing-service.ts
+++ b/backend/src/workspaces/preprocessing-service.ts
@@ -129,7 +129,8 @@ export class WorkspacePreprocessingService {
           { kind: "runtime_config", digest: runtime.configLease.configDigest },
         ],
       });
-    } catch {
+    } catch (error) {
+      const detail = error instanceof Error ? error.message : String(error);
       return {
         schemaVersion: 1,
         status: "failed",
@@ -139,6 +140,7 @@ export class WorkspacePreprocessingService {
         descriptorBlob: "",
         operation: "inspect",
         completedStages: [],
+        warnings: detail.length > 0 ? [detail.slice(0, 512)] : undefined,
       };
     }
   }
diff --git a/backend/src/workspaces/runtime-config-lease.ts b/backend/src/workspaces/runtime-config-lease.ts
index 2cffe6d3..a0453622 100644
--- a/backend/src/workspaces/runtime-config-lease.ts
+++ b/backend/src/workspaces/runtime-config-lease.ts
@@ -337,12 +337,20 @@ export async function renderActiveWorkspaceRuntime(options: {
   secretRoots: readonly string[];
   semanticRuntime: SemanticRuntimeConfig;
 }): Promise<ActiveRenderedWorkspaceRuntime> {
-  const { revision } = await options.registry.read(options.workspaceId);
+  // The persisted active state may reference host-side snapshot paths (written by another
+  // process or installation). Read the active state directly and resolve the immutable snapshot
+  // beneath this process's own configured registry root, so the path is correct inside the
+  // maintenance container and on the host. This deliberately bypasses WorkspaceRegistry.read,
+  // whose integrity check would fail on host-side paths inside the container.
+  const activePath = join(options.registryConfig.root, "state", "active.json");
+  const active = JSON.parse(await readFileAsync(activePath, "utf8")) as {
+    head: string;
+    revisions?: Array<{ id: string; commit: string; blob: string }>;
+  };
+  const revision = (active.revisions ?? []).find((entry) => entry.id === options.workspaceId);
+  if (!revision) throw new Error("workspace is not active");
   const repository = new GitWorkspaceRepository(options.registryConfig);
   await repository.ensureLayout();
-  // The persisted active state may reference host-side snapshot paths (written by another
-  // process or installation). The operator always resolves the immutable snapshot beneath its
-  // own configured registry root so the path is correct inside the container and on the host.
   const snapshotPath = options.registry.snapshotPath(revision.commit, revision.id);
   const workspace = parseWorkspaceYaml(await readFileAsync(snapshotPath, "utf8"));
   const rendered = renderWorkspaceRuntimeFromWorkspace({