Mac fails to boot or start after the macOS update. Whatever is preventing your Mac from starting up, follow these 5 simple solutions to get it working again. If you have data loss problem after macOS update, EaseUS Data Recovery Wizard for Mac provides tried-and-true data recovery service to you. After updating to Catalina I can't connect to the VPN with the message User authentication failed. Any idea how to fix or troubleshoot this problem? The only logs I've found are in /var/system/wifi.log: Wed Oct 9 23:47:06.462 processIPv4Changes: ARP/NDP offloads disabled, not programming the offload.

• Macbook Not Updating To Catalina 10.15.7
• Macbook Pro Not Updating To Catalina

This page covers 5 fixes for Mac won't boot or start issue after macOS Big Sur, Catalina, Sierra or older macOS update issue. If you are with this issue, follow to make your Mac computer work now:

macOS has now been updated to 11.0, and many Mac users are trying to upgrade to the newest version. While for most it's a usual pleasurable experience, for some this update had downsides. Some users complain that their Mac computers won't boot after installing new macOS Big Sur/Catalina. When Mac fails, it usually can't boot or start up properly. If you are faced with this situation, the most important thing should be recovering data from the unbootable Mac because:

• Your attempts to fix the Mac not booting issue may write new data on this Mac, which will overwrite the old data and make it irrecoverable.
• Recovering data before the complex fixes can avoid data loss.

EaseUS Mac data recovery software is able to recover data from unbootable Macs after update. It creates a bootable media that enables you to recover data from Mac hard drive (If you only have one Mac). What's more, it recovers data from failed internal Mac hard drive, APFS boot drive, and unmountable APFS boot volume, etc. If you have two Mac devices, take out the hard drive and connect it to the other Mac. Download EaseUS Data Recovery Wizard for Mac on that Mac device, and recover data from the hard drive.

Then, you can read on and Fix the 'Mac won't boot after update' issue after you have successfully got data from the drive.

1. Reset the PRAM / NVRAM

NVRAM refers to special memory sections on your Mac that store data that persists even when the Mac is shut off, such as volume settings and screen resolution. Resetting that data isn't harmful! In some cases, after performing this step, your Mac will restart normally.

• Restart your Mac
• Hold down all of these keys: 'Command', 'Option', 'P' and 'R', and turn on the Mac. (It's the same keys to reset the PRAM).
• Keep holding the keys down until you hear the Mac restart again.

You may see a progress bar on startup. If the progress bar fills up and then the Mac starts up, you're probably good to go. If not, reset SMC.

2. Reset the SMC

In some situations, you may need to reset your Mac's SMC (System Management Controller).

• Shut the Mac down.
• Unplug all cables.
• Wait for a few minutes.
• Plug the cables back in and start up the Mac.

If you've got a Mac desktop, unplug it for 15 seconds and then plug it in and after five seconds press the power button.

3. Boot Mac in Safe Mode

Safe Mode is a stripped-down version of the Mac operating system that can be useful if you are trying to troubleshoot issues with your Mac.

• Start your Mac, press and hold the 'Shift' key, and make sure your Mac has at least 9 GB of free space.
• When the login window appears to release the shift key and log in. You may be required to log in twice if you have FileVault turned on. Then restart the device.

Wait patiently till Mac computer finish the reboot process.

4. Run Disk Utility in Recovery Mode

If your Mac is booting but the operating system isn't loading up, you may have a corrupted drive. Luckily it is possible to fix this in Recovery Mode. In Recovery Mode you can restore from a Time Machine backup, use Disk Utility to verify and repair connected drives, check your internet connection, get help online using Safari, and install or reinstall macOS.

• Make sure the Mac is off. If it's stuck on a grey, blue or white screen, just hold down Mac's power button for several seconds until it shuts off.
• Hold down the 'Command' and 'R' keys, and power the Mac back up again. Keep pressing 'Cmd' + 'R' while your Mac is booting up.
• Once your Mac starts in Recovery Mode you can have access to 'Utilities'. Click 'Disk Utility', locate the icon for your Mac's drive, and click 'Verify Disk'.

5. Reinstall macOS Big Sur/Catalina/Sierra

The last method to fix macOS Big Sur, Catalina or Sierra fails to boot after update error is to reinstall macOS.

• You can download wanted macOS Big Sur/Catalina/Sierra and create a bootable USB drive to clean install macOS Big Sur/Catalina/Sierra on your computer again.
• You can also boot into Recovery mode (Solution 4), and then click to install the latest OS and follow the onscreen prompts. Our article on resetting a Mac to factory settings has more information on reinstalling macOS.

If your Mac does not respond after trying these tips, contact Apple Support or a certified Apple Repair Center. It’s likely there is a problem with your logic board or other internal hardware.

We all know that it’s important to “stay patched, so you stay secure.” But macOS is making that a bit harder these days. Apple really wants you to upgrade to macOS Big Sur, but if you’re not ready for that big jump, it may be hard to notice that you have macOS Catalina and Safari updates to apply.

macOS Big Sur is a huge change and it’s usually a good idea to let the bleeding edge folks work out the kinks. It’s also not a bad idea to wait for Apple to make at least its first update before jumping on the new hotness. You may have applications that are not yet macOS Big Sur-compatible so be cautious with a big upgrade like this. I’m not a proponent of waiting a long time to upgrade to the latest OS but caution, especially on such a big change, is definitely warranted. While you’re waiting for the OS to stabilize, you want to keep macOS Catalina up to date, but Apple makes it difficult to see just how to do that.

While you’re still on macOS Catalina, if you open System Preferences and select Software Update, you’ll see the icon for macOS Big Sur with an obvious “Upgrade Now” button. But we don’t want to upgrade to macOS Big Sur just yet.

When I took the screenshot for this post, I actually had updates to macOS Catalina and Safari waiting for me, but it sure wasn’t obvious they were there.

Under the icon for macOS Big Sur, there was some smaller text that said, “Other updates are available” and blue link text that said “More info…”

Click on that tiny More info link to reveal the updates you really need to apply. In my example, I had macOS Catalina 10.15.7 Supplemental Update waiting, and the notes below clearly say that this update “improves the security of macOS.” There was also a Safari update to 14.0.1 which had some speed enhancements but also security fixes, including the removal of support for Adobe Flash. You really want this update!

After you apply any Safari or macOS Catalina updates, the Software Update Preference Pane will still say “More info…” As shown below:

Macbook Not Updating To Catalina 10.15.7

But if you click the link now, it will take you to the Apple web page telling you about all the awesome features of macOS Big Sur. I presume this “More info…” link will change back to showing you security updates for macOS Catalina and Safari when new ones are available, so you’ll have to be vigilant and pay attention in looking for the updates.

I don’t like that Apple has made it so undiscoverable that security updates are awaiting us. I would really prefer that they had made two equally-obvious buttons, one to upgrade to macOS Big Sur and one to update macOS Catalina and Safari. They’re doing a disservice to the community by making it this hidden. As I said up front, I’m a big proponent of getting on a new OS when it’s practical to do so, but it is the user’s decision when to do it and shouldn’t be tricked into what could be a catastrophic upgrade.

Macbook Pro Not Updating To Catalina

Since you’re probably the family nerd if you’re reading or hearing this, please pass this post along to your friends and family so they stay patched so they stay secure.