diff --git a/apps/desktop/src/app/services/services.module.ts b/apps/desktop/src/app/services/services.module.ts
index e4dd144fa20..59021a556e4 100644
--- a/apps/desktop/src/app/services/services.module.ts
+++ b/apps/desktop/src/app/services/services.module.ts
@@ -203,8 +203,16 @@ const safeProviders: SafeProvider[] = [
     // We manually override the value of SUPPORTS_SECURE_STORAGE here to avoid
     // the TokenService having to inject the PlatformUtilsService which introduces a
     // circular dependency on Desktop only.
+    //
+    // For Windows portable builds, we disable secure storage to ensure tokens are
+    // stored on disk (in bitwarden-appdata) rather than in Windows Credential
+    // Manager, making them portable across machines. This allows users to move the USB drive
+    // between computers while maintaining authentication.
+    //
+    // Note: Portable mode does not use secure storage for read/write/clear operations,
+    // preventing any collision with tokens from a regular desktop installation.
     provide: SUPPORTS_SECURE_STORAGE,
-    useValue: ELECTRON_SUPPORTS_SECURE_STORAGE,
+    useValue: ELECTRON_SUPPORTS_SECURE_STORAGE && !ipc.platform.isWindowsPortable,
   }),
   safeProvider({
     provide: DEFAULT_VAULT_TIMEOUT,
diff --git a/apps/desktop/src/platform/preload.ts b/apps/desktop/src/platform/preload.ts
index a45ac753b3f..5f643242a9c 100644
--- a/apps/desktop/src/platform/preload.ts
+++ b/apps/desktop/src/platform/preload.ts
@@ -17,6 +17,7 @@ import {
   isFlatpak,
   isMacAppStore,
   isSnapStore,
+  isWindowsPortable,
   isWindowsStore,
 } from "../utils";
 
@@ -133,6 +134,7 @@ export default {
   isDev: isDev(),
   isMacAppStore: isMacAppStore(),
   isWindowsStore: isWindowsStore(),
+  isWindowsPortable: isWindowsPortable(),
   isFlatpak: isFlatpak(),
   isSnapStore: isSnapStore(),
   isAppImage: isAppImage(),
diff --git a/libs/common/src/auth/services/token.service.ts b/libs/common/src/auth/services/token.service.ts
index c02bc85f124..ce272705341 100644
--- a/libs/common/src/auth/services/token.service.ts
+++ b/libs/common/src/auth/services/token.service.ts
@@ -445,13 +445,15 @@ export class TokenService implements TokenServiceAbstraction {
     // we can't determine storage location w/out vaultTimeoutAction and vaultTimeout
     // but we can simply clear all locations to avoid the need to require those parameters.
 
+    // When secure storage is supported, clear the encryption key from secure storage.
+    // When not supported (e.g., portable builds), tokens are stored on disk and this step is skipped.
     if (this.platformSupportsSecureStorage) {
-      // Always clear the access token key when clearing the access token
-      // The next set of the access token will create a new access token key
+      // Always clear the access token key when clearing the access token.
+      // The next set of the access token will create a new access token key.
       await this.clearAccessTokenKey(userId);
     }
 
-    // Platform doesn't support secure storage, so use state provider implementation
+    // Clear tokens from disk storage (all platforms)
     await this.singleUserStateProvider.get(userId, ACCESS_TOKEN_DISK).update((_) => null, {
       shouldUpdate: (previousValue) => previousValue !== null,
     });
@@ -478,6 +480,9 @@ export class TokenService implements TokenServiceAbstraction {
       return null;
     }
 
+    // When platformSupportsSecureStorage=true, tokens on disk are encrypted and require
+    // decryption keys from secure storage. When false (e.g., portable builds), tokens are
+    // stored on disk.
     if (this.platformSupportsSecureStorage) {
       let accessTokenKey: AccessTokenKey;
       try {
@@ -1118,6 +1123,9 @@ export class TokenService implements TokenServiceAbstraction {
     ) {
       return TokenStorageLocation.Memory;
     } else {
+      // Secure storage (e.g., OS credential manager) is preferred when available.
+      // Desktop portable builds set platformSupportsSecureStorage=false to store tokens
+      // on disk for portability across machines.
       if (useSecureStorage && this.platformSupportsSecureStorage) {
         return TokenStorageLocation.SecureStorage;
       }