diff --git a/macOS/APIExample/Examples/Advanced/AudioMixing/AudioMixing.swift b/macOS/APIExample/Examples/Advanced/AudioMixing/AudioMixing.swift
index b1551d603..9c0630aab 100644
--- a/macOS/APIExample/Examples/Advanced/AudioMixing/AudioMixing.swift
+++ b/macOS/APIExample/Examples/Advanced/AudioMixing/AudioMixing.swift
@@ -91,7 +91,7 @@ class AudioMixing: BaseViewController {
     @IBOutlet weak var selectMicsPicker: Picker!
     var mics:[AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectMicsPicker.picker.addItems(withTitles: self.mics.map {$0.deviceName ?? "unknown"})
             }
         }
diff --git a/macOS/APIExample/Examples/Advanced/CustomAudioRender/CustomAudioRender.swift b/macOS/APIExample/Examples/Advanced/CustomAudioRender/CustomAudioRender.swift
index 5479f782c..cdc53e4e0 100644
--- a/macOS/APIExample/Examples/Advanced/CustomAudioRender/CustomAudioRender.swift
+++ b/macOS/APIExample/Examples/Advanced/CustomAudioRender/CustomAudioRender.swift
@@ -23,7 +23,7 @@ class CustomAudioRender: BaseViewController {
     @IBOutlet weak var selectMicsPicker: Picker!
     var mics: [AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectMicsPicker.picker.addItems(withTitles: self.mics.map {$0.deviceName ?? "unknown"})
             }
         }
diff --git a/macOS/APIExample/Examples/Advanced/CustomAudioSource/CustomAudioSource.swift b/macOS/APIExample/Examples/Advanced/CustomAudioSource/CustomAudioSource.swift
index 02c4cdf8a..5e094a599 100644
--- a/macOS/APIExample/Examples/Advanced/CustomAudioSource/CustomAudioSource.swift
+++ b/macOS/APIExample/Examples/Advanced/CustomAudioSource/CustomAudioSource.swift
@@ -22,7 +22,7 @@ class CustomAudioSource: BaseViewController {
     @IBOutlet weak var selectMicsPicker: Picker!
     var mics: [AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectMicsPicker.picker.addItems(withTitles: self.mics.map {$0.deviceName ?? "unknown"})
             }
         }
diff --git a/macOS/APIExample/Examples/Advanced/PrecallTest/PrecallTest.swift b/macOS/APIExample/Examples/Advanced/PrecallTest/PrecallTest.swift
index 1dd491038..4ed062e88 100644
--- a/macOS/APIExample/Examples/Advanced/PrecallTest/PrecallTest.swift
+++ b/macOS/APIExample/Examples/Advanced/PrecallTest/PrecallTest.swift
@@ -37,7 +37,7 @@ class PrecallTest: BaseViewController {
     @IBOutlet weak var echoValidatePopover: NSView!
     var cameras:[AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.cameraPicker.addItems(withTitles: self.cameras.map({ (device: AgoraRtcDeviceInfo) -> String in
                     return (device.deviceName ?? "")
                 }))
@@ -46,7 +46,7 @@ class PrecallTest: BaseViewController {
     }
     var mics:[AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.micPicker.addItems(withTitles: self.mics.map({ (device: AgoraRtcDeviceInfo) -> String in
                     return (device.deviceName ?? "")
                 }))
@@ -55,7 +55,7 @@ class PrecallTest: BaseViewController {
     }
     var speakers:[AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.speakerPicker.addItems(withTitles: self.speakers.map({ (device: AgoraRtcDeviceInfo) -> String in
                     return (device.deviceName ?? "")
                 }))
@@ -303,6 +303,7 @@ extension PrecallTest: AgoraRtcEngineDelegate {
     /// @params totalVolume Total volume after audio mixing. The value range is [0,255].
     func rtcEngine(_ engine: AgoraRtcEngineKit, reportAudioVolumeIndicationOfSpeakers speakers: [AgoraRtcAudioVolumeInfo], totalVolume: Int) {
         for speaker in speakers {
+            print("reportAudioVolumeIndicationOfSpeakers:\(speaker.uid), \(speaker.volume)")
             if(speaker.uid == 0) {
                 micTestingVolumeIndicator.doubleValue = Double(speaker.volume)
             }
diff --git a/macOS/APIExample/Examples/Advanced/RawAudioData/RawAudioData.swift b/macOS/APIExample/Examples/Advanced/RawAudioData/RawAudioData.swift
index f72bb4016..8e9754189 100644
--- a/macOS/APIExample/Examples/Advanced/RawAudioData/RawAudioData.swift
+++ b/macOS/APIExample/Examples/Advanced/RawAudioData/RawAudioData.swift
@@ -23,7 +23,7 @@ class RawAudioData: BaseViewController {
     @IBOutlet weak var selectMicsPicker: Picker!
     var mics: [AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectMicsPicker.picker.addItems(withTitles: self.mics.map {$0.deviceName ?? "unknown"})
             }
         }
diff --git a/macOS/APIExample/Examples/Advanced/VoiceChanger/VoiceChanger.swift b/macOS/APIExample/Examples/Advanced/VoiceChanger/VoiceChanger.swift
index 30e3896aa..954b860dd 100644
--- a/macOS/APIExample/Examples/Advanced/VoiceChanger/VoiceChanger.swift
+++ b/macOS/APIExample/Examples/Advanced/VoiceChanger/VoiceChanger.swift
@@ -57,7 +57,7 @@ class VoiceChanger: BaseViewController {
     @IBOutlet weak var selectMicsPicker: Picker!
     var mics:[AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectMicsPicker.picker.addItems(withTitles: self.mics.map {$0.deviceName ?? "unknown"})
             }
         }
diff --git a/macOS/APIExample/Examples/Basic/JoinChannelAudio/JoinChannelAudio.swift b/macOS/APIExample/Examples/Basic/JoinChannelAudio/JoinChannelAudio.swift
index 10613f478..6f7853644 100644
--- a/macOS/APIExample/Examples/Basic/JoinChannelAudio/JoinChannelAudio.swift
+++ b/macOS/APIExample/Examples/Basic/JoinChannelAudio/JoinChannelAudio.swift
@@ -79,7 +79,7 @@ class JoinChannelAudioMain: BaseViewController {
     @IBOutlet weak var selectMicsPicker: Picker!
     var mics:[AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectMicsPicker.picker.addItems(withTitles: self.mics.map {$0.deviceName ?? "unknown"})
             }
         }
diff --git a/macOS/APIExample/Examples/Basic/JoinChannelVideo/JoinChannelVideo.swift b/macOS/APIExample/Examples/Basic/JoinChannelVideo/JoinChannelVideo.swift
index 6a5a5c1eb..5feda8e3c 100644
--- a/macOS/APIExample/Examples/Basic/JoinChannelVideo/JoinChannelVideo.swift
+++ b/macOS/APIExample/Examples/Basic/JoinChannelVideo/JoinChannelVideo.swift
@@ -22,7 +22,7 @@ class JoinChannelVideoMain: BaseViewController {
     @IBOutlet weak var selectCameraPicker: Picker!
     var cameras: [AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectCameraPicker.picker.addItems(withTitles: self.cameras.map {$0.deviceName ?? "unknown"})
             }
         }
@@ -135,7 +135,7 @@ class JoinChannelVideoMain: BaseViewController {
     @IBOutlet weak var selectMicsPicker: Picker!
     var mics: [AgoraRtcDeviceInfo] = [] {
         didSet {
-            DispatchQueue.main.async {[unowned self] in
+            DispatchQueue.main.async {
                 self.selectMicsPicker.picker.addItems(withTitles: self.mics.map {$0.deviceName ?? "unknown"})
             }
         }
@@ -268,7 +268,7 @@ class JoinChannelVideoMain: BaseViewController {
         initChannelField()
         initJoinChannelButton()
     }
-        
+            
     func layoutVideos(_ count: Int) {
         videos = []
         for i in 0...count - 1 {
diff --git a/macOS/APIExample/ViewController.swift b/macOS/APIExample/ViewController.swift
index 2290ab6b5..328e2ef9d 100644
--- a/macOS/APIExample/ViewController.swift
+++ b/macOS/APIExample/ViewController.swift
@@ -110,7 +110,6 @@ extension MenuController: NSTableViewDataSource, NSTableViewDelegate {
     
     func tableViewSelectionDidChange(_ notification: Notification) {
         if tableView.selectedRow >= 0 && tableView.selectedRow < menus.count {
-            Thread.sleep(forTimeInterval: 1)
             loadSplitViewItem(item: menus[tableView.selectedRow])
         }
     }