Since updating to MacOS 27, my Mac takes noticeably longer to open the settings window, and switching between my browser and notes now stutters. I read that post-update “indexing” can temporarily slow everything down, but I’m not sure that term explains this much lag. Does that claim hold up, or is this abnormal?
Don’t start deleting caches or reinstalling macOS yet. Post-update indexing can absolutely cause stuttering while Spotlight, Photos, and cloud files rebuild their databases, especially if storage is nearly full. It should ease after several hours of being plugged in and awake, though. If it’s still just as bad after a day or two, check Activity Monitor for sustained CPU or disk use and confirm you have plenty of free space. At that point, the lag is less likely to be normal indexing.
As a minor dark secret, a major version update can cause old background login items/extensions to misbehave (even after the process is finished). If the stutter persists after a reboot, try disabling these old background processes (before coming to any conclusions about the OS being slow).
Some sluggishness immediately after a major upgrade is expected. Persistent animation and app-switching stutter after the Mac has spent an idle night plugged in is not something I’d write off as indexing.
Try disconnecting any external monitor, dock, or DisplayLink adapter and use the built-in display at its default scaling. WindowServer can become the bottleneck after an update, especially with scaled resolutions or third-party display drivers. That produces exactly the “everything works, but the interface feels sticky” symptom without showing one application consuming all the CPU.
Safe Mode is a useful dividing line too. If the desktop becomes smooth there, the hardware and basic OS installation are probably okay, and I’d focus on display software, menu bar utilities, window managers, VPN clients, or other system-level add-ons. If it still stutters in Safe Mode with peripherals removed, then check for a follow-up macOS update and run Disk Utility’s First Aid before considering a reinstall. Turning on Reduce Motion may hide the annoyance, but it does not fix the underlying slowdown.
If you’re on an older Intel Mac, don’t expect it to bounce back. The newest release tends to run heavier on that hardware, and no amount of indexing patience fixes that. The Safe Mode test @stacktigersync mentioned is still worth doing, but if it drags there too on an aging machine, that’s just the cost of the upgrade.
Create a temporary user account and spend a few minutes in that clean desktop before doing anything drastic. Open System Settings, launch Notes, and try the same browser switching that feels choppy in your normal account. It’s a quick way to separate an OS-wide slowdown from a problem tied to your user profile.
If the temporary account is smooth, I’d look at browser extensions, menu bar apps, cloud syncing, and anything that restores a pile of windows when you log in. You can have low CPU usage overall while a sync client or extension keeps causing tiny stalls. In that case, reinstalling the whole OS would be a lot of work for the wrong problem.
If both accounts lag, check whether Low Power Mode got enabled during the upgrade and whether the Mac is running unusually hot. A warm Intel Mac with the fans going hard may be throttling, but I wouldn’t accept “old hardware, deal with it” based only on its age. An abrupt change right after an update still deserves basic troubleshooting.
Do a full shutdown rather than another restart, leave it off briefly, then boot with all accessories unplugged. Give it some time at the desktop before opening your normal workload. If it remains jerky in a fresh account with nothing attached, that’s a much stronger sign that the update itself, a driver, or the installation needs attention rather than Spotlight simply being busy.
Do not use low CPU utilization as an argument that the system is done with background processes because the way I see it, ‘slow’ does not mean ‘processor’, it’s a problem with memory management that you’d see when switching applications. Go to Activity Monitor and check the Memory tab while the stutter persists. Memory pressure and the amount of Swap Used is a bigger concern than the percentage listed as used. If the graph is entering the yellow or red section or the Swap Used number is increasing, quit the browser entirely instead of just closing the windows, then re-open it and try again with only a few tabs open. Restoring dozens of tabs after an update can cause hiccups throughout the operating system even if none one individual process is using a lot of memory.
This is why I wouldn’t assume an older Intel machine has simply reached the end of the road, as @blueninja8568 suggests. Limited RAM combined with nearly full storage can make swapping much more noticeable, but that gives you something specific to test. Turn off “reopen windows when logging back in” for one boot as well. Otherwise every app may quietly return and recreate the same memory problem.
If Memory Pressure is green and swapping is light, then the suggestions about the display-driver and background-item are probably more plausible. On the other hand, if ending the browser and preventing its windows from reopening does not seem to help, it will not be worth waiting for indexing to finish. The update may have uncovered a particularly memory-intensive session, but it may not be a good idea to say that the whole OS became slower.
Update every third-party utility that has Accessibility, Input Monitoring, screen recording, or system-extension access, then shut down and boot again. Those tools can hook into every window, so an outdated clipboard manager, mouse driver, antivirus app, or window utility can make built-in apps stutter too.
Disabling a login item may not unload its extension until the next boot, which is an easy detail to miss. Short-lived sluggishness after an upgrade is normal; unchanged lag after the background work settles is not.