diff --git a/src/modules/features/SetupManager.ts b/src/modules/features/SetupManager.ts
index 51edf441..b5b88410 100644
--- a/src/modules/features/SetupManager.ts
+++ b/src/modules/features/SetupManager.ts
@@ -5,6 +5,7 @@ import {
     LOG_LEVEL_VERBOSE,
 } from "@vrtmrz/livesync-commonlib/compat/common/types";
 import { createNewVaultSettings } from "@vrtmrz/livesync-commonlib/settings";
+import { generateAdaptiveJournalRepositoryIdV1 } from "@vrtmrz/livesync-commonlib/adaptive-journal";
 import {
     defaultRemoteProviderRegistry,
     upsertRemoteConfigurationInPlace,
@@ -71,6 +72,29 @@ export const enum UserMode {
     Update = "unknown", // Alias for Unknown for better readability
 }
 
+type AdaptiveJournalIdentitySetting = {
+    expectedRepositoryId?: string;
+    journalFormat?: string;
+};
+
+async function prepareAdaptiveRepositoryIdentityForSetup<T extends object>(
+    settings: T,
+    userMode: UserMode
+): Promise<T> {
+    const adaptiveSettings = settings as T & AdaptiveJournalIdentitySetting;
+    if (
+        userMode !== UserMode.NewUser ||
+        adaptiveSettings.journalFormat !== "adaptive-v1" ||
+        (adaptiveSettings.expectedRepositoryId ?? "").trim() !== ""
+    ) {
+        return settings;
+    }
+    return {
+        ...settings,
+        expectedRepositoryId: await generateAdaptiveJournalRepositoryIdV1(),
+    };
+}
+
 /**
  * Setup Manager to handle onboarding and configuration setup
  */
@@ -210,10 +234,15 @@ export class SetupManager extends AbstractModule {
         }
 
         const newSetting = copySettingsForRemoteProfileUpdate(currentSetting);
+        const preparedSettings = await prepareAdaptiveRepositoryIdentityForSetup(configuration.settings, userMode);
+        const preparedConfiguration = {
+            ...configuration,
+            settings: preparedSettings,
+        } as BuiltInRemoteConfiguration;
         if (activate) {
-            defaultRemoteProviderRegistry.applyConfiguration(newSetting, configuration);
+            defaultRemoteProviderRegistry.applyConfiguration(newSetting, preparedConfiguration);
         } else {
-            Object.assign(newSetting, configuration.settings);
+            Object.assign(newSetting, preparedSettings);
         }
 
         const activateForP2P = defaultRemoteProviderRegistry.supportsActivationRole(type, "p2p");
diff --git a/src/modules/features/SetupManager.unit.spec.ts b/src/modules/features/SetupManager.unit.spec.ts
index 74eb2f6d..3df59188 100644
--- a/src/modules/features/SetupManager.unit.spec.ts
+++ b/src/modules/features/SetupManager.unit.spec.ts
@@ -462,6 +462,60 @@ describe("SetupManager", () => {
         expect(nextSettings).toEqual(expect.objectContaining({ ...bucketSettings, remoteType: REMOTE_MINIO }));
     });
 
+    it("preselects a repository identity during fresh Adaptive Object Storage onboarding", async () => {
+        const { manager, setting, dialogManager } = createSetupManager();
+        dialogManager.openWithExplicitCancel
+            .mockResolvedValueOnce({
+                endpoint: "https://storage.example",
+                accessKey: "key",
+                secretKey: "secret",
+                bucket: "notes",
+                region: "auto",
+                bucketPrefix: "",
+                useCustomRequestHandler: false,
+                bucketCustomHeaders: "",
+                forcePathStyle: true,
+                expectedRepositoryId: "",
+                journalFormat: "adaptive-v1",
+                packReadPolicy: "whole-pack",
+            })
+            .mockResolvedValueOnce(true);
+
+        await manager.onBucketManualSetup(UserMode.NewUser, setting.currentSettings());
+
+        const current = setting.currentSettings();
+        expect(current.expectedRepositoryId).toMatch(/^[A-Za-z0-9_-]{43}$/u);
+        const activeProfile = current.remoteConfigurations[current.activeConfigurationId];
+        expect(activeProfile?.uri).toContain(`expectedRepositoryId=${current.expectedRepositoryId}`);
+    });
+
+    it("leaves an existing-device Adaptive Object Storage attachment on trust on first use", async () => {
+        const { manager, setting, dialogManager } = createSetupManager();
+        dialogManager.openWithExplicitCancel
+            .mockResolvedValueOnce({
+                endpoint: "https://storage.example",
+                accessKey: "key",
+                secretKey: "secret",
+                bucket: "notes",
+                region: "auto",
+                bucketPrefix: "",
+                useCustomRequestHandler: false,
+                bucketCustomHeaders: "",
+                forcePathStyle: true,
+                expectedRepositoryId: "",
+                journalFormat: "adaptive-v1",
+                packReadPolicy: "whole-pack",
+            })
+            .mockResolvedValueOnce(true);
+
+        await manager.onBucketManualSetup(UserMode.ExistingUser, setting.currentSettings());
+
+        const current = setting.currentSettings();
+        expect(current.expectedRepositoryId).toBe("");
+        const activeProfile = current.remoteConfigurations[current.activeConfigurationId];
+        expect(activeProfile?.uri).not.toContain("expectedRepositoryId=");
+    });
+
     it("creates and selects a P2P profile during fresh manual onboarding", async () => {
         const { manager, setting, dialogManager } = createSetupManager();
         setting.settings = {