This post is for MacBook owners who upgraded to macOS 27 and now feel the Mac is slower than before, whether you use it for college work, accounts, teaching or home use. You will learn what is normal in the first days, and then a short order of checks: Activity Monitor, storage, login items, restart and Software Update. You will also see the signs that mean the problem is not the software at all.
Why is my MacBook slow after the macOS 27 upgrade?
Short answer: A big macOS upgrade makes the Mac rebuild its search index (the list Spotlight uses to find files) and often re-scan photos. This happens in the background for a day or two and can make the Mac feel slow. If it is still slow after two days on power, check Activity Monitor, free storage and login items, then Software Update. Apple released macOS 27 on 14 September 2026, for Apple silicon Macs only.
Is the first-day slowness normal?
Yes, it often is. After an upgrade the Mac does housekeeping: Spotlight indexes files again, the Photos app may analyse your library, and apps update their data. You may notice warm palm rests, fan noise or sluggish apps. Plug in the charger, leave the lid open, and use the Mac lightly. Give it a day or two. If you have a large photo library, it may take longer.
Macs that use Intel processors cannot run macOS 27. If yours is an Intel Mac, it stays on macOS 26, so this post does not apply. Our guide on checking whether your Mac works with macOS 27 explains how to tell.
Steps to find the cause
1. Open Activity Monitor
Open Finder, then Applications, then Utilities, then Activity Monitor. Click the CPU tab and sort by the percentage column. An app staying at a very high figure for a long time is the likely cause. System names such as mds or photoanalysisd are normal during re-indexing. If an app you installed is the one, update it or remove it. Check the Memory tab too: heavy use with a red memory pressure graph means the Mac is short of memory.
2. Check storage
Open the Apple menu, then System Settings, then General, then Storage. A Mac with very little free space slows down, because it has no room to work. Aim to keep a healthy margin free. Do not delete files you cannot replace; back up first. Apple silicon Macs have memory and storage built in, and they cannot be upgraded later.
3. Remove login items
Open System Settings, then General, then Login Items. Remove apps that you do not need to start every time. The wording can differ slightly between versions.
4. Restart, then check Software Update
Restart the Mac properly. Then open System Settings, General, Software Update to see whether a newer macOS 27 point release is offered. We cannot say which one is current on the day you read this, so check Apple's security releases page and Software Update for today's position.
Heat, power cuts and a patchy connection
In hot Indian rooms, a MacBook that is already warm slows itself down to cool. Work on a hard flat surface, not a bed. Do not start an upgrade or a large download on weak broadband, and avoid it during frequent power cuts: a Mac that loses power in the middle of an update can fail to start. Keep it plugged in. Never switch the Mac off by holding the power button while an update is running. Our guide to backing up before macOS 27 covers the safe order.
When to get help
Ask a technician if:
- The Mac is still slow after several days and all the checks above.
- It freezes, restarts by itself or shows a spinning wheel often.
- It runs hot or loud even when you are doing very little.
- The battery drains much faster than it used to.
A MacBook under Apple's warranty should go to Apple's own service first. We repair MacBooks out of warranty or when the owner chooses independent repair. See our MacBook hanging and freezing page and the Apple repair page. We accept laptops by courier from anywhere in India, with doorstep service in Hyderabad through our Apple service page for Secunderabad. ₹149 doorstep visit fee, waived when you approve laptop repair with us.
A note from the LRW Engineer Team
Do the simple things in order and change one thing at a time, so you know what helped. Keep a current backup before any clean-up. If the Mac is also hot or loud, do not keep restarting it over and over: a quick physical check of the fan and vents may be what it needs.