macOS App Store Error 100 — Cannot Connect to App Store Fix

What Does This Error Mean?

App Store Error 100 means your Mac could not connect to Apple's servers to load the App Store. This is almost always caused by a network problem, a wrong date and time setting, or a corrupted App Store cache on your Mac. It is rarely a problem on Apple's end — the fix is usually on your Mac.

Affected Models

MacBook Air
MacBook Pro
iMac
Mac Mini
Mac Studio
Mac Pro

Common Causes

Your Mac's date and time are wrong, causing Apple's security certificate to be rejected
The App Store cache files on your Mac are corrupted
A VPN or firewall is blocking the connection to Apple's servers
Your internet connection is unstable or you are behind a restrictive network
You are signed into the wrong Apple ID or your Apple ID session has expired

How to Fix It

Check your date and time. Go to System Settings > General > Date & Time. Make sure 'Set time and time zone automatically' is turned on.

A wrong date by even one day can cause App Store to reject Apple's security certificate and refuse to connect.
Sign out of the App Store and sign back in. Open the App Store, click your name at the bottom of the sidebar, and click Sign Out. Then sign back in with your Apple ID.

An expired session can cause connection errors. Signing out and back in refreshes your authentication.
Clear the App Store cache. Open Finder, click Go in the menu bar, hold the Option key, and click Library. Navigate to Caches and delete the folder named com.apple.appstore.

This forces the App Store to rebuild its cache from scratch. Quit the App Store before doing this.
Disable your VPN if you have one. VPNs can route traffic in ways that block Apple's servers. Turn off the VPN, restart the App Store, and try again.

If the App Store works with the VPN off, the VPN is the cause. Try changing the VPN server or contacting your VPN provider.
Restart your router. Unplug your router from power for 30 seconds, then plug it back in. Wait for it to fully reconnect, then try the App Store again.

A quick router restart clears temporary network issues and often resolves connection errors.

When to Call a Professional

This error is almost always fixable at home. You should only contact Apple Support if the error continues after trying all fixes and you can confirm your internet and date/time settings are correct. Apple Support can check if there is an account-level issue with your Apple ID.

Frequently Asked Questions

Is Apple's App Store down?

It is possible but rare. Check Apple's System Status page at apple.com/support/systemstatus to see if the App Store is experiencing an outage. If the status shows green, the problem is on your end.

Why does the date and time affect the App Store?

Apple's servers use security certificates that are only valid during certain time periods. If your Mac thinks the date is wrong, it may think the certificate has expired and refuse to connect. Keeping your date and time set automatically prevents this.

Can I download apps another way if the App Store is broken?

For most Mac apps, no — the App Store is the only official source. Some apps (like Google Chrome or Firefox) offer direct downloads from their websites. Be careful downloading software from unofficial sources — only use the developer's official website.