diff --git a/media/libaudioclient/IAudioPolicyService.cpp b/media/libaudioclient/IAudioPolicyService.cpp
index 0b98502..c0d5388 100644
--- a/media/libaudioclient/IAudioPolicyService.cpp
+++ b/media/libaudioclient/IAudioPolicyService.cpp
@@ -872,13 +872,15 @@
         case INIT_STREAM_VOLUME:
         case SET_STREAM_VOLUME:
         case REGISTER_POLICY_MIXES:
-        case SET_MASTER_MONO:
-            if (IPCThreadState::self()->getCallingUid() >= AID_APP_START) {
+        case SET_MASTER_MONO: {
+            uid_t multiUserClientUid = IPCThreadState::self()->getCallingUid() % AID_USER_OFFSET;
+            if (multiUserClientUid >= AID_APP_START) {
                 ALOGW("%s: transaction %d received from PID %d unauthorized UID %d",
                       __func__, code, IPCThreadState::self()->getCallingPid(),
                       IPCThreadState::self()->getCallingUid());
                 return INVALID_OPERATION;
             }
+        } break;
         default:
             break;
     }