diff --git a/indra/llaudio/llaudioengine_fmodstudio.cpp b/indra/llaudio/llaudioengine_fmodstudio.cpp
index 36b35efb47..fab0bfabda 100644
--- a/indra/llaudio/llaudioengine_fmodstudio.cpp
+++ b/indra/llaudio/llaudioengine_fmodstudio.cpp
@@ -138,7 +138,7 @@ static FMOD_RESULT F_CALL systemCallback(FMOD_SYSTEM *system, FMOD_SYSTEM_CALLBA
                 std::unique_lock lock(iAudioDeviceMutex, 3s);
                 // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
                 // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-                if (not lock.owns_lock())
+                if (!lock.owns_lock())
                 {
                     LL_INFOS() << "Could not access the audio device mutex, trying again later" << LL_ENDL;
                     return FMOD_OK; // Could be a FMOD_ERR_ALREADY_LOCKED;
@@ -433,7 +433,7 @@ void LLAudioEngine_FMODSTUDIO::setDevice(const LLUUID& device_uuid)
     std::unique_lock lock(iAudioDeviceMutex, 3s);
     // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
     // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-    if (not lock.owns_lock())
+    if (!lock.owns_lock())
     {
         LL_INFOS() << "Could not access the audio device mutex, trying again later" << LL_ENDL;
         return;
diff --git a/indra/llwebrtc/llwebrtc.cpp b/indra/llwebrtc/llwebrtc.cpp
index 2ed9cfc071..4aeb152278 100644
--- a/indra/llwebrtc/llwebrtc.cpp
+++ b/indra/llwebrtc/llwebrtc.cpp
@@ -481,7 +481,7 @@ void LLWebRTCImpl::workerDeployDevices()
     std::unique_lock lock(iAudioDeviceMutex, 3s);
     // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
     // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-    if (not lock.owns_lock())
+    if (!lock.owns_lock())
     {
         return;
     }
@@ -664,7 +664,7 @@ void LLWebRTCImpl::updateDevices()
     std::unique_lock lock(iAudioDeviceMutex, 3s);
     // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
     // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-    if (not lock.owns_lock())
+    if (!lock.owns_lock())
     {
         return;
     }
@@ -859,7 +859,7 @@ void LLWebRTCImpl::intSetMute(bool mute, int delay_ms)
                     std::unique_lock lock(iAudioDeviceMutex, 3s);
                     // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
                     // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-                    if (not lock.owns_lock())
+                    if (!lock.owns_lock())
                     {
                         return;
                     }
@@ -920,7 +920,7 @@ void LLWebRTCImpl::intSetMute(bool mute, int delay_ms)
                     std::unique_lock lock(iAudioDeviceMutex, 3s);
                     // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
                     // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-                    if (not lock.owns_lock())
+                    if (!lock.owns_lock())
                     {
                         return;
                     }
diff --git a/indra/newview/llvoicevivox.cpp b/indra/newview/llvoicevivox.cpp
index 6ae5441270..11f0c96083 100644
--- a/indra/newview/llvoicevivox.cpp
+++ b/indra/newview/llvoicevivox.cpp
@@ -2423,7 +2423,7 @@ void LLVivoxVoiceClient::sendCaptureAndRenderDevices()
         std::unique_lock lock(iAudioDeviceMutex, 3s);
         // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
         // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-        if (not lock.owns_lock())
+        if (!lock.owns_lock())
         {
             LL_INFOS() << "Could not access the audio device mutex, trying again later" << LL_ENDL;
             return;
diff --git a/indra/newview/llvoicewebrtc.cpp b/indra/newview/llvoicewebrtc.cpp
index 046fa40a91..c7d04fd5bf 100644
--- a/indra/newview/llvoicewebrtc.cpp
+++ b/indra/newview/llvoicewebrtc.cpp
@@ -767,7 +767,7 @@ void LLWebRTCVoiceClient::OnDevicesChangedImpl(const llwebrtc::LLWebRTCVoiceDevi
     std::unique_lock lock(iAudioDeviceMutex, 3s);
     // If the lock could not be accessed, return as we don't have hardware access and will need to try again another pass.
     // Prevents threads from interacting with the hardware at the same time as other audio/voice threads.
-    if (not lock.owns_lock())
+    if (!lock.owns_lock())
     {
         LL_INFOS() << "Could not access the audio device mutex, trying again later" << LL_ENDL;
         return;