How to Fix Slow Mac After macOS Tahoe Update

28Sep

After the wait, macOS Tahoe 26 arrived on September 15, 2025, bringing a sleek new Liquid Glass design, enhanced Spotlight, deeper AI features, and exciting new apps. While many users love the new capabilities, some Macs—especially older or heavily used ones—may feel slower or laggy after upgrading.

If your Mac is running slow after updating to macOS Tahoe 26, don’t worry. This guide covers the most effective troubleshooting steps and fixes to improve your MacBook, iMac, Mac Mini, or Mac Pro performance post-update.

Before your start (initial checks)

Before diving into fixes, it’s important to diagnose the root cause to avoid unnecessary steps or risk to your data.

Hardware Issues – If your Mac has SSD problems, thermal throttling (overheating), or other hardware faults, no software fix can help. We recommend you visit an Apple Store or authorized service provider for diagnostics and repair.

Software Conflicts – Check if incompatible or resource-heavy apps are causing slowdowns. Some older apps may not yet be optimized for Tahoe.

Create a Backup – Always back up your Mac before troubleshooting or applying fixes. Use Time Machine or third-party backup tools to safeguard your data.

Check Your Mac’s Environment – Macs throttle CPU performance when overheating. Ensure proper ventilation and avoid hot ambient temperatures before blaming the update.

Quick and effective fixes for macOS Tahoe slowdown

Now that you have identified the problem and made a backup for extra security, we can check these easy and quick solutions to improve your Mac’s performance.

1. macOS slow right after an update

If this is the case for you and your Mac is feeling slow right after you completed the installation and updated the OS, the best and quickest fix you can try is to restart your Mac. Most apps and services can keep running and start hogging up all the resources, leading to slowdowns and lag. So try the following:

Click on the Apple button and bring up the drop-down box
Now, click the “Restart” button and let your device restart.

Note: You can hold the power button for a few seconds for a hard restart. However, if the restart does not solve the problem, you can always look at the following fixes below.

2. Use Activity Monitor to kill apps and background tasks

The following fix is not as easy as the first one, but it does help when you need that extra bit of performance. Most apps run in the background for better access but take a lot of RAM and CPU usage. This can slow down your computer, especially if you have an old Mac.

For instance, if you’re not using the latest and greatest M1/M2 Mac, expect to see some lags.

The system monitoring solution is quite adequate, and you can do this by:

Head on to your Applications folder and then to Utilities
Next, double-click on “Activity Monitor” to get it running
After your screen looks something like the screenshot above, go to the CPU tab. Here you will see a list of running applications in the background, and click on any that you want to kill.
Finally, select all the apps you want to kill and click on the “X” button to kill the apps and free up some extra performance. You can also kill any misbehaving apps that take up too much performance.

Note: You can also access “Activity Monitor” through Spotlight. Press Command + Spacebar, type in “Activity Monitor”, and hit the Return key. You can check the percentage of CPU/Memory an app uses, and if something looks unnatural such as 60% use, kill it to increase performance.

3. Check storage space

Another critical issue that can slow your Mac after an update is the storage space available on the drive. Because Apple packs new features, a new macOS version will use more storage space.

As you can see from the screenshot below, only 30GB of total storage space is left. As a result, the system is experiencing some random errors and lags.

If you have the same problem, we recommend you get rid of unnecessary system files by using a 3rd-party Mac cleaner tool or get an external drive to store some of the data. The minimum amount of free storage should be somewhere in the neighborhood of 60-70GB of free space for smooth and seamless operation. You can check your Mac’s storage by:

On macOS Tahoe: System Settings > General > Storage
On older macOS versions: About This Mac > Storage

Note: You can also click the “Manage” button and use the “Optimized Storage” option Apple provides to clear your Mac of unwanted junk files.

4. Let Spotlight reindex after the update

Spotlight goes into overdrive after major macOS upgrades, reindexing all your files. During this process, you may notice sluggish performance, high fan speeds, or apps stuttering.

Fix: Give it a day or two. Keep your Mac plugged in and idle when possible. You can check indexing status by clicking the Spotlight icon in the menu bar.

5. Fix iCloud sync overload

After updating, iCloud often kicks into high gear—resyncing your entire photo library, desktop & documents, and app data. This can hammer CPU, RAM, and network, making your Mac feel sluggish.

You can try:

Open System Settings > Apple ID > iCloud to check what’s syncing.
Temporarily pause heavy services like Photos or iCloud Drive if you need performance right away.
Keep your Mac plugged in and connected to stable Wi-Fi to let the sync complete faster.

Tip: Once the initial post-update sync finishes, performance usually improves on its own.

6. Disable Stage Manager (optional)

Stage Manager is useful for organizing apps, but it can be resource-heavy on some Macs. With macOS 26 Tahoe, Apple introduced Liquid Glass, a lighter and more fluid windowing system.

💡 Pro Tip:

If you notice performance dips, try disabling Stage Manager (Control Center > Stage Manager > Off).
Most users will find Liquid Glass alone is enough for smooth multitasking.
Keep Stage Manager enabled only if you rely on its grouping features — otherwise, turning it off may give your MacBook extra breathing room.

7. Update to the latest build

macOS Tahoe is just out and there are many bugs you must deal with. Not to mention all the performance hits you can expect with lags and stutters. So, constantly update the version with new builds and the stable version when Apple releases it. You can check for possible updates by:

Click on the Apple icon in the top left corner and select “System Settings” from the list
Now, choose “Software Update” and let it check for available updates
If you see something like the screenshot above, then click on the “Software Update…” button
This will start the update process, and once that is completed, you will be greeted with the latest build

Note: You can expect more performance and better optimization as Apple is still working with the new OS. Increasing performance and decreasing the required power will help improve the overall experience with all their compatible devices.

8. Update your apps

Does your updated Mac become slower when you launch a particular app? It could be that the app has not been optimized for macOS Tahoe. Even though most developers roll out their updates during the macOS beta period, some might be delayed.

Therefore, you must ensure that you have updated all the apps on your Mac. You can do it different ways.

To update all the apps you have installed from the Mac App Store, you can use the ‘Update All’ button that you can find on MAS. It will download the latest version from the developers.

For third-party apps, you can use a dedicated app updater utility. For instance, the Updater utility that comes in the Macpaw CleanMyMac package will do the job. It will download the latest version of third-party apps from their official website and make things easy.

Alternatively, you can use Homebrew to install and manage the many apps on your Mac.

9. Remove unnecessary login items/startup apps

Start-up apps are helpful, but they take up a lot of performance. If you can live with starting apps yourself every time you boot into the OS and don’t need them to launch automatically, you can disable those to get that extra bit of performance and have faster booting times.

Doing so will also fix your slow Mac and improve your experience with macOS. You can remove the startup apps by:

Head on to “System Settings” by clicking on the Apple icon and selecting the respective tab
Next, click on “Users and Groups”, select your User, and finally, on the “Login Items” tab
Now, you’ll be able to see a list of startup apps, as shown in the screenshot above, and you can simply remove those by selecting an app and clicking on the “-” button

Note: You can add startup apps by clicking on the “+” button and selecting an app. However, remove all the apps from the startup list if you want the best performance.

10. Clear cache

The term cache is something that most of you must be familiar with. Most people have heard the word for their phones, but the cache is also a big part of macOS. This is usually used to speed up processes and apps by storing some app data in the cache.

Still, the system’s overall performance can gradually decrease if the files exceed a lot of storage.

There are three types of cache used by macOS: System Cache, Browser Cache, and User Cache. We do not recommend you delete System Cache as it messes with the applications, but you can go ahead and delete the browser cache to free up memory and improve performance. To do so:

Go to Finder and click on “Go”, and choose the “Go to Folder” option
Now, enter the following path ~/Library/Caches and hit enter
Next, you will be greeted with the folders as shown in the screenshot above, and all you have to do is select the cache files and delete them.

Note: Remember not to mess with any system cache files, as it can bring many bugs and issues, which will worsen your experience. Oh, and don’t delete the folders, just the files, and you can head on to Chrome or Safari’s settings to clear the browser cache.

You could also rely on a dedicated Mac optimizer software – with the right expectations to quickly detox the unwanted caches from the operating system. For example, the System Junk module in CleanMyMac allows you to easily remove temporary files, outdated caches, and application residue.

11. Clean up your cluttered home screen

This fix is quite simple. All you need to do is remove clutter from your home screen. Apps and Widgets can take up a lot of performance if you’re not careful, so go ahead and remove all the unnecessary app icons and widgets from your home screen and keep it clean.

The result should look something like the screenshot below.

Finally, after removing all the clutter, bring in all the apps you use regularly and add those to the home screen for quick access. However, remember to keep it minimal and don’t clutter your home screen again.

12. Reduce transparency and motion

macOS Tahoe’s Liquid Glass interface is stunning, but the constant transparency and layering effects can tax older GPUs.

Hence, one way to make your apps run more quickly and your experience seamless is by disabling the Reduce Motion and Reduce Transparency options. You may want to try this option if you want to upgrade a really old Mac to macOS Tahoe.

So, by giving up fancy animations and transparency, you can get better performance. It is a useful solution if you have an older Mac.

You can do this by:

Click on the “Apple” button on the top left corner of the screen and select the “System Settings” option
Next, choose “Accessibility” and then “Display”, as shown in the screenshot above
Finally, check the Reduce Motion and Reduce Transparency checkboxes and close the Accessibility panel

Note: This will remove all transparency and motion animations which may feel a little weird initially, but you should get used to it reasonably soon. Hence, the result uses fewer system resources as there are fewer things to render, which often makes your Mac faster.

13. Consider a clean install (last resort)

The final option to improve your device performance is to either entirely revert to macOS Sequoia or do a fresh and clean install for macOS Tahoe. This will help clean your device thoroughly, and you can do this by:

Revert back to Sequoia:

Firstly, restart your device and hold down the Shift + Option + Command and R keys
Next, from the “Recovery Mode” click on the “Reinstall macOS Sequoia” button.
Now, you can follow the steps and downgrade macOS back to Sequoia.

Clean install macOS Tahoe:

Once you’re back in Sequoia, go to the “System Settings” panel and select “Software Update”.
You will be able to see the Tahoe update there
Finally, click on “Update…” and let it do a clean install on your Mac

Note: This process will erase all your data, so make a backup before proceeding with the above steps.

Finally, if nothing worked for you and even reinstalling Sequoia with a clean install didn’t solve the issue, you are left with two other options. These fixes can take days and money, so make sure you are ready. So, the solutions are:

Take it to an Apple Store – Taking your Mac to an Apple store will ensure you receive the best fix for your device. The Store can check for any hardware and software issues and remove any problems or replace faulty parts. However, do note that it can cost you some money and time. Therefore, we recommend this method only as a last resort.

Get a cleaning service – If your Mac is facing issues with heat and is lagging due to the CPU being throttled down, you can take it to a cleaning service and get it cleaned out. The fans gather dust and get clogged up, which raises the internal temperature. So, if you have an older model, it can seriously hamper your device’s performance.

⚠️ Don’t rush to wipe your Mac. Even brand-new Macs slow down after months if you don’t perform basic care. Most of the time, the OS isn’t the problem — it’s old caches, too many login apps, or Finder/iCloud syncing dragging things down. Try these simple steps first before considering a clean reinstall.

FAQs

Why is my Mac slow after Tahoe update?

New resource demands from AI, Spotlight, and enhanced features strain hardware, especially on older Macs.

Can clearing cache improve performance?

Yes, clearing browser and user cache can help, but avoid deleting system cache files to prevent instability.

How do I reset PRAM/NVRAM?

On Intel Macs: Restart and hold Option + Command + P + R until the second startup sound or Apple logo. On Apple Silicon Macs: NVRAM resets automatically; a simple restart is enough.

Final words

A slow Mac after updating to macOS Tahoe is common but usually fixable with the right optimizations. Restarting, freeing space, updating software, and managing startup items are your first lines of defense.

When issues persist, a clean install or consulting Apple Support can help. With patience and maintenance, your Mac can continue running smoothly on macOS Tahoe.

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How to Fix Slow Mac After macOS Tahoe Update

Before your start (initial checks)