Apps that will be killed off in macOS Catalina include Transmist 4.1.7, 1Password 2.12.2, iStats Menu 2.9 and QuickBooks 2015. You can view the full list of the apps at The Tape Drive. In macOS, you can change what app opens a specific file type from the file itself. Right-click a file that you want to change the default app that opens, and select Get Info.

Force quit the app, then open it again

iPhone, iPad, iPod touch: Force the app to close.
Apple Watch: With the app open, press and hold the side button to show the power options. Then press and hold the Digital Crown to quit the app.
Apple TV: Double press the TV/Home button and swipe left or right to find the app with the issue. Then swipe up to close the app. You can’t force apps to quit on Apple TV (3rd generation).

Restart your device

Restart your iPhone, iPad, iPod touch, Apple Watch, or Apple TV. Then open the app to see if it works as expected.

Check for updates

Make sure that your device has the latest version of iOS or iPadOS, watchOS, or tvOS. Then check for app updates.

iPhone, iPad, iPod touch, or Apple Watch: You can manually update apps. You might need a Wi-Fi connection to update some apps on your iPhone, iPad, or iPod touch.
Apple TV: Go to Settings > Apps and turn on Automatically Update Apps. If you don't have automatic updates turned on, you can open the App Store, go to the Purchased tab, and open an app's product page to see if an update is available.

Reinstall the app

iPhone, iPad, iPod touch: Open the Settings app. Tap General, then tap iPhone Storage (or iPad Storage). Tap the affected app, then tap Offload app. Tap Offload app again. Wait a moment for the app to offload, then tap Reinstall App.
Apple TV: Highlight the app on the Home screen, then press and hold the Touch surface until the app jiggles. Press Play/Pause, then select Delete. Open the App Store and redownload the app. Some apps require subscriptions for activation. If you can't activate the app or you don’t remember your sign-in information, contact the app developer.
Apple Watch: Open the Watch app on your iPhone and tap the My Watch tab. Scroll to the app you want to remove, then tap it. Turn off Show App on Apple Watch, and wait for it to disappear from your watch's Home screen. To reinstall the app, scroll down to Available Apps in the My Watch tab and tap Install.

Contact the app developer

If you're having an issue with an Apple app, contact Apple Support. If it's a third-party app, contact the app developer.

Learn more

Get help with unfamiliar charges and in-app purchases.
If you can’t install or update an app, or if it’s stuck waiting, learn what to do.
Get help with audio, video, or power on Apple TV.

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After summer comes macOS. This long-standing tradition started by Apple is the most exciting moment of the year — seeing your Macs improve and gain new bells and whistles. In 2019, we're welcoming Catalina, the 10.15 version of macOS named after Catalina island in California. Apparently, it's hot.

The operating system boasts a whole lot of new macOS features like Sidecar, iOS apps porting, and major Photos update. To try the features right away, you can install Catalina from the Software Update tab.

However, be prepared for some troubleshooting. The acquaintance with the new macOS doesn't always go smooth — and with macOS 10.15 deeming support for lots of software, many things will not go smooth. We've collected the key macOS Catalina issues you may encounter, along with the ways to fix them.

macOS 10.15 Catalina problems and their fixes

Giving up Catalina is a decision you can choose to make. But before rolling back, ensure you use every bit of advice as to how you can fix the common problems. Sometimes, a quick fix can solve your concerns.

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Beta or not, you can safely install any version of the new macOS. Setapp and its 150+ apps will solve every Mac concern you have.

Problems with macOS Catalina you can solve:

macOS 10.15 Catalina won't install

This is the classic problem that arises with every macOS release: The installation won't start or you face the 'Catalina installation stuck' problem — when it freezes and you see no progress on the install. No matter how many times you start over, you keep getting an error trying to install Catalina.'

How to fix:

Apple recommends to reset SMC. Shut down your Mac, and hold Shift + Ctrl + Option + Power button for about 10 seconds, with your cable plugged in. Click on the power button and wait for your Mac to start up.
Try resetting NVRAM or PRAM. Shut down your Mac, and hold Option + Command + P + R for about 20 seconds. Wait for your computer to restart.
Reinstall from macOS recovery. Hold Option + Command + R to reinstall. Once you see the startup screen, start the installation again.
Some users reported they were prompted to enter administrator password several times to complete the installation. So it might be something for you to try as well.
In most cases, macOS Catalina cannot be installed on Macintosh HD, because it doesn't have enough disk space. If you install Catalina on top of your current operating system, the computer will keep all the files and still need free space for Catalina. So the easiest fix would be to clean up your system with CleanMyMac X before upgrading. All the system junk, app leftovers, and unneeded files will go away in a minute.
Backup your disk and run a clean install. This will wipe away your current system files, leaving space for macOS Catalina — so yes, this option is for the brave. If you use a solid backup solution, you'll keep your data safe, though. Get Backup Pro is a nice way to do it — unlike Apple's Time Machine, the app allows running bootable backups.

Say you've cleared up and backed up your disk. But your Mac still gets stuck at the installation and shows 'not enough space' error, so you can't get out of the cycle. In this case, there's another fix you can try:

Reinstall Mojave. No worries, this won't delete your disk. Reboot your Mac and hold Command + R to enter the Recovery Mode. Click Reinstall macOS.
Restore from your backup. If you have a Time Machine backup, enter the Recovery Mode again and select 'Restore from Time Machine Backup.' Select the backup from the list and restore your files. Check out how to use apple time machine.

Some users also report they tried to reboot into Safe Mode and take the installation from there; the others used a newly created admin user — but most attempts have been unsuccessful.

We must agree that macOS 10.15 is one of the slowest systems in terms of installation. But if you use the hacks described above and have a little patience, you'll be able to get to the 'Catalina installed' point.

Find more information about how to update mac os the right way.

If you can't login after upgrading to Catalina

There's a known problem of failing to login after the installation. Unfortunately, the only way to fix it — at least for now — would be to roll back to Mojave:

Clean up your Mac with CleanMyMac X and backup your data.
Save passwords to ensure you don't lose license keys and settings.
Create a bootable installer of Mojave (after Catalina goes public, you can download Mojave here).
Delete macOS Catalina: Apple menu > Restart > Command + R > Disk Utility > your startup disk > Erase.

One of the things Mac users are particularly excited about is the new Sidecar feature. It comes as a handy solution for those wanting to expand their workspaces. You can either mirror your Mac's screen to iPad or use your iPad's screen as an extension of a Mac.

If the only reason you're here is because you want Sidecar, we have to warn you it might not work with your new macOS. Reddit is full of user reports about the feature unavailable on macOS Catalina. Most likely, this is the issue of compatibility.

App Opens And Closes Right Away On Macos