Your Mac Can Be Fast Again — Here's What It Takes
A Mac that crawls after a macOS update is one of the most common — and most fixable — tech problems on the Costa Blanca. Post-update slowdowns are almost never a hardware failure; they're caused by background indexing, bloated caches, login item chaos, and the occasional rogue process hogging your CPU. You can resolve most cases yourself in under an hour, with zero technical background required. No trip to a chain store, no expensive "diagnostics fee," no waiting three weeks for a replacement part that was never needed.
Before you start: make sure your Mac is plugged into power, you know your Apple ID password, and you have at least 15 GB of free storage. That last one matters more than most people think.
Step 1: Give Spotlight a Chance to Finish Indexing
Every time macOS updates, Spotlight re-indexes your entire drive. During this process — which can take anywhere from 20 minutes to several hours on older machines — your Mac will feel like it's running through treacle. This is normal, temporary, and not a sign your Mac is dying.
- Click the Spotlight magnifying glass (top-right menu bar) and type anything.
- If you see a progress bar under the results, indexing is still running. Leave the Mac on, plugged in, and go make a coffee.
- Do not force-restart during indexing — that just restarts the clock.
If Spotlight shows no progress bar and your Mac is still sluggish after 24 hours, move to Step 2.
Step 2: Clear the System and App Caches
macOS updates frequently leave stale cache files behind. Old cache data conflicts with new system libraries and causes apps to stutter, freeze, or take forever to open. Clearing them is safe and often delivers an immediate speed improvement.
- Open Finder, click Go in the menu bar, then hold Option — a hidden "Library" folder appears. Click it.
- Open the Caches folder. Select everything inside and move it to the Bin. Do not delete the Caches folder itself — just its contents.
- Repeat the same process for System > Library > Caches (you'll need your admin password).
- Empty the Bin, then restart your Mac.
Third-party cleaner apps like CleanMyMac can automate this, but the manual method above is free and equally effective. Don't pay for a tool that does what Finder already can.
Step 3: Audit Your Login Items and Background Agents
Software updates are sneaky. Half the time, apps use the update process to re-enable background services you deliberately switched off months ago. Too many login items means your Mac spends the first five minutes after boot fighting itself instead of serving you.
- Go to System Settings > General > Login Items & Extensions (macOS Ventura and later) or System Preferences > Users & Groups > Login Items on older versions.
- Look at the list ruthlessly. Do you actually need Dropbox, OneDrive, Spotify, Teams, and your printer utility all launching at startup? Probably not.
- Select anything you don't need immediately at boot and click the minus (–) button to remove it.
- Also scroll down to Background Items — these are hidden agents running silently. Toggle off anything from software you rarely use.
Restart after making changes. Many Macs see a dramatic improvement from this step alone.
Step 4: Use Activity Monitor to Hunt Down the CPU Hog
If your Mac is still sluggish, something specific is eating your processor. Activity Monitor is your weapon — it shows exactly which process is burning resources in real time.
- Press Command + Space, type Activity Monitor, and open it.
- Click the CPU tab and sort by % CPU — highest first.
- Anything consistently above 80–90% CPU that isn't something you're actively using is a problem. Common offenders post-update: mds_stores (Spotlight — goes away on its own), kernel_task (thermal throttling — more on this below), and WindowServer (display issues).
- For most non-system processes hogging CPU: select the process, click the X button at the top left of Activity Monitor, and choose Force Quit.
If kernel_task is the culprit at sky-high CPU usage, your Mac is thermally throttling — it's deliberately slowing itself down because it's overheating. Shut it down, let it cool for 20 minutes in the shade (not a sunny windowsill in Alicante), and try again. Persistent overheating means the fans or thermal paste need attention. That's a hardware job — call us.
Step 5: Free Up Storage Space
macOS needs a minimum of 10–15 GB of free space to operate normally. When your drive is nearly full, virtual memory can't function, swap files pile up, and everything grinds. Post-update installs also leave behind old system data that you no longer need.
- Go to Apple Menu > About This Mac > Storage (or System Settings > General > Storage on newer macOS).
- Click Manage and use Apple's built-in recommendations: Optimise Storage, Reduce Clutter, and Empty Bin Automatically.
- Under Reduce Clutter, look for "iOS Files" and "Garage Band Sound Library" — these are often multi-gigabyte space hogs that most people never touch.
- Check your Downloads folder. Seriously. Most people's Downloads folder is a graveyard of 4GB installers from 2019.
Target: get to at least 15 GB free. More is better. If your drive is simply too small for your workload, an external SSD or a RAM upgrade might be the real answer — and both are far cheaper than a new Mac.
Step 6: Reset the SMC and NVRAM
Still slow? Two quick resets can clear low-level configuration glitches that survive even a full restart. These sound scarier than they are — they don't delete your files or settings.
Reset NVRAM (all Macs):
- Shut down your Mac.
- Power on and immediately hold Option + Command + P + R for about 20 seconds.
- Release and let the Mac boot normally.
- Note: M1/M2/M3 Macs reset NVRAM automatically at boot — skip this step if you have Apple Silicon.
Reset SMC (Intel Macs only):
- Shut down. Hold Shift + Control + Option + Power button for 10 seconds.
- Release all keys, then press the Power button normally to start up.
Apple Silicon Mac owners: SMC doesn't exist on M-series chips. If you've done all the steps above and an M1/M2/M3 Mac is still crawling, the issue is likely software-deep — a clean macOS reinstall or a call to us is the next move.
If Things Go Wrong: Troubleshooting the Troubleshooting
Sometimes the fixes above don't stick, or they create new problems. Here's what to do:
- Mac won't boot after cache deletion: Hold Command + R on startup to enter Recovery Mode. Use Disk Utility to run First Aid on your drive, then restart.
- Activity Monitor shows nothing obviously wrong but Mac is still slow: Create a new user account (System Settings > Users & Groups) and log into it. If the new account is fast, the problem is in your user profile — corrupted preferences or a bad app. Start disabling apps one by one.
- SMC/NVRAM reset made things worse: It shouldn't — but if display settings or startup disk changed, just go back into System Settings and correct them. Nothing was damaged.
- Your Mac is on macOS Monterey or earlier and still crawling: Check whether your Mac is actually supported by the update you installed. Running an unsupported Mac on a patched OS via OpenCore or similar tools is a recipe for permanent slowdown.
You'll Know It Worked When…
Boot your Mac fresh after completing these steps. Open Safari, your email client, and one or two apps you use daily — all at the same time. If they launch within a few seconds, stop beachballing mid-task, and Activity Monitor shows no single process above 20–30% CPU at idle, you've fixed it. Your Mac should feel at least as fast as it did before the update — often noticeably faster, because you've cleaned up years of digital cobwebs along the way.
If it's still dragging after all six steps, the problem is deeper than software — and that's exactly the kind of thing we diagnose here at Campoverde Repair without charging you a fortune just to look at it. Bring it in or give us a call.
Key Takeaways
- Post-update Mac slowdowns are almost always software or configuration issues — not a sign you need a new machine.
- Spotlight indexing causes temporary slowdowns for up to 24 hours after a major update; wait it out before panicking.
- Clearing system caches and auditing login items fixes the majority of cases — and costs nothing.
- Activity Monitor tells you exactly which process is the culprit; use it before guessing.
- Your Mac needs at least 15 GB of free storage to run normally — anything less and performance tanks regardless of what else you fix.
Frequently asked questions
Why is my Mac so slow after a macOS update?
The most common cause is Spotlight re-indexing your drive after the update, which can take up to 24 hours and significantly slow your Mac during that time. Other culprits include stale cache files, too many login items, and background processes hogging CPU — all fixable without any specialist tools.
How do I speed up my Mac after updating to the latest macOS?
Start by waiting 24 hours for Spotlight indexing to finish, then clear your system caches via the Library folder, and audit your login items in System Settings. If still slow, open Activity Monitor to find which process is consuming the most CPU and force-quit it.
Will resetting NVRAM or SMC fix a slow Mac after an update?
It can — NVRAM and SMC resets clear low-level configuration glitches that can persist through software updates. They're safe to perform, take under two minutes, and don't delete any of your files or personal settings. Note that M1, M2, and M3 Macs don't have an SMC to reset.
How much free storage does a Mac need to run properly?
Apple recommends keeping at least 10–15 GB of free space on your Mac's drive at all times. When storage drops below this threshold, macOS can't manage virtual memory efficiently, which causes noticeable slowdowns, app freezes, and beachballing.
Should I take my Mac to a repair shop if it's slow after an update?
Only if the standard software fixes — cache clearing, login item audit, Activity Monitor checks, and SMC/NVRAM resets — don't resolve the issue after a full attempt. Persistent slowdowns after all software steps usually indicate a hardware issue like overheating, failing storage, or insufficient RAM.