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Previously, I tried to install every Catalina update via Recovery Mode because it always failed in System Preference -> Software update.

Unable to verify software update

Reference: Reinstall from macOS Recovery , it said

Option-⌘-R

Upgrade to the latest macOS that is compatible with your Mac.

That works well until I tried to install/upgrade Big…


This is a basic case for one-to-one relationship using left join multiple tables. Let’s start from describing the use case in a scenario:

Say your Sales team has a contact database stored all the customers’ contact, and each contact has its owner who is a Sales agent in your team.


I can imagine most of the application back-end servers are leveraging AWS SNS to send push notifications to android and iOS devices for it integrated well with FCM and APNS.

One day, I found my development iOS app is not receiving VOIP push notification anymore! This is extremely scaring for…


audio device menu

Previously, we introduced How to add audio device action sheet to your iOS app, I believe there is the same need for android app. So here we go again.

Similar to iOS devices, there are 3 typical audio routes: DEFAULT, SPEAKER, BLUETOOTH.

The DEFAULT route is the handset and will…


audio devices action sheet from Callkit

When developing an app with music, video, call functions, it always comes up this requirement:

How to select a desired audio device

Like the above image, it’s from CallKit where you can select the desired audio output from this action sheet.

First, we have to understand how many audio routes…


What a beautiful island like Catalina!

However it probably gonna to be:

What a painful experience to update Electron app for Catalina!

It was exciting after upgrading macOS from Mojave to Catalina and see the beautiful desktop wallpaper, even it took like FOREVER to complete!

The excitement didn’t last more…


I have been fighting this issue for quite a long time, since I bought a new Mac mini early this year and restored the system with my TimeMachine backup, every time when there is a Mojave update comes out, I always got this “update failed” warning.

Unable to verify software update

And my first idea…

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store