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Mac User Guide
- Welcome
- What’s new in macOS Tahoe
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- Intro to Apple Intelligence
- Translate messages and calls
- Create original images with Image Playground
- Create your own emoji with Genmoji
- Use Apple Intelligence with Siri
- Find the right words with Writing Tools
- Summarize notifications and reduce interruptions
- Use ChatGPT with Apple Intelligence
- Apple Intelligence and privacy
- Block access to Apple Intelligence features
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- Intro to Continuity
- Use AirDrop to send items to nearby devices
- Hand off tasks between devices
- Control your iPhone from your Mac
- Copy and paste between devices
- Stream video and audio with AirPlay
- Make and receive calls and text messages on your Mac
- Use your iPhone internet connection with your Mac
- Share your Wi-Fi password with another device
- Use iPhone as a webcam
- Insert sketches, photos, and scans from iPhone or iPad
- Unlock your Mac with Apple Watch
- Use your iPad as a second display
- Use one keyboard and mouse to control Mac and iPad
- Sync music, books, and more between devices
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- Get started
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- Accessibility features for vision
- Get started with VoiceOver
- Zoom in on what’s around you
- Zoom in on your Mac screen
- Increase font size and icons
- Adjust the display colors
- Hover to zoom in on text and colors
- Listen to or change how text appears in apps
- Customize onscreen motion
- Increase the size of what’s on your screen
- Make the pointer easier to see
- Have your Mac speak text that’s on the screen
- Resources for your Mac
- Resources for your Apple devices
- Copyright and trademarks

Determine which disk started up your Mac
Some Mac computers can be started up from a network volume, a different disk, or another operating system.
Important: If you have a Mac with an Apple T2 Security Chip, added security features may be set to prevent the computer from starting up from an external startup disk. See What is the Startup Security Utility? If you have a Mac with Apple silicon, see Change the security policy.
On your Mac, choose Apple menu
> System Settings, then click General
in the sidebar. (You may need to scroll down.)Click Startup Disk on the right.
Open Startup Disk settings for me
Your startup disk appears selected.
See alsoChange your Mac startup disk
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