MacBook slow? Finding the cause – from full storage to battery and SSD

In short: first check how full the storage is (System Settings → General → Storage) and what runs automatically at every boot under "Login Items" – that alone often solves the problem. On MacBooks with an M1 to M5 chip, full storage is usually the cause, in our experience. On Intel models, the workshop most often dealt with the drive (a new SSD or recovering the data from the old hard drive), then the logic board, and less often a cleaning, a reinstall or the battery. If the MacBook stays sluggish even with free storage, the diagnosis is free: in person in Hamburg-Altona or from anywhere in Germany by mail-in via emonis.com, with free DHL shipping both ways.

Is your MacBook slow – does it stutter, boot slowly or keep showing the beachball? First, here is what you can check yourself, sorted by the words customers use to describe the problem at intake. Where we have workshop figures, you will also find what the cause turned out to be. This applies to the MacBook Air and MacBook Pro, from the old Intel models with a hard drive up to the M6 chip. The first question is always: Intel or Apple Silicon? Apple menu → "About This Mac" tells you: "Chip: Apple M…" or "Processor: … Intel …" (how to find out). If the MacBook no longer responds at all (frozen screen, even the mouse pointer stuck), that is not a speed problem. How to force a restart is explained in the guide MacBook won't start or turn on.

Which case is yours?

Why is my MacBook so slow? Sluggish all the time, whatever you do

"It's just very slow", "too slow" – that is what intake notes say most often: no trigger, no single app, everything has been sluggish for weeks or months. First look at step 1 to see how full the storage is, then at "About This Mac" to see which chip is inside. On a MacBook with an M1 to M5 chip, nearly full storage is the most common reason in our experience, and you can usually fix it without a workshop. On Intel models, the workshop most often dealt with the drive: a new SSD in place of the old hard drive or an SSD that had become too small (see Old MacBook), or recovering the data from a failing drive. Then came a repair on the logic board, and less often a cleaning, a reinstall or the battery.

MacBook suddenly slow – overnight

"Suddenly extremely slow since yesterday" often comes after a large download, a data migration or an update. Open Activity Monitor (Applications → Utilities) and sort the "CPU" tab by load. A single process under constant heavy load is almost always the culprit: quit or update the app. Also check the storage (step 1): a single large download can fill a nearly full SSD to the brim. If both look normal, check the battery: a weak battery can slow a MacBook down noticeably, so a suddenly sluggish MacBook does not necessarily mean the SSD or RAM is failing. How to check the battery condition and cycle count is explained in MacBook battery cycles. When a replacement is due and what it costs is covered in MacBook battery replacement.

MacBook slow after an update

"Slow since updating to the new macOS": first give the system a day or two – step 5 explains why. Then check the storage (step 1: an update needs space and leaves caches behind) and the login items, and install any pending updates for your apps. If an older Intel MacBook runs a macOS it is really too old for, that slows it down permanently. Which macOS versions are available for download and how to install an older macOS is explained in Download macOS and create a boot stick. If the MacBook does not start at all after the update, see the guide MacBook won't start. In the workshop, this symptom had no single typical finding: everything from a reinstall to the SSD to the battery came up.

MacBook keeps hanging – beachball, stutters, freezes briefly

"Keeps hanging", "the beachball all the time", "freezes for seconds": the first suspect is the Mac running short of memory while you work. Open Activity Monitor and go to the "Memory" tab. If the "Memory Pressure" graph is yellow or red, close apps and browser tabs and check the "Swap Used" value (step 1). If only one app hangs, press Option (⌥) + Command (⌘) + Esc and choose "Force Quit". If the whole Mac hangs, including the mouse pointer, see the guide MacBook won't start. When the hanging persisted, the workshop's cost estimate named the logic board.

MacBook boots slowly – takes forever to start

"Takes forever to boot", "nothing happens for minutes after logging in": the number one cause is full storage (step 1), followed directly by the list of login items that launch at every boot. The quick test is safe mode (step 5): there, macOS loads no login items and only the extensions it needs. If the Mac runs noticeably faster after you log in, this list is the cause. An Intel MacBook with a mechanical hard drive, on the other hand, boots slowly by design, and only an SSD helps there (Old MacBook).

Old MacBook slow – hard drive instead of SSD

"It's just old, but actually still fine": on a MacBook Pro without a Retina display (up to 2012), the reason is usually the mechanical hard drive. The 13" entry model from mid-2012 shipped with a 500 GB hard drive (5,400 rpm), and an SSD cost extra. Every app launch and every system start waits for the mechanics. On the Retina models up to 2015, it is more likely an SSD that has become too small. In older Intel MacBooks up to late 2015 (MacBook Air up to 2017), we fit a modern SSD, with data migration and a fresh macOS. An SSD upgrade starts at €180 incl. VAT. What else is possible for your model is listed under MacBook upgrades. If the old hard drive makes noises or copying stops partway, back up your data first, with our help if necessary: MacBook data recovery. According to Apple, a Fusion Drive (hard drive plus small flash storage) was an option for the iMac and Mac mini from late 2012, but never in a MacBook. For a slow iMac, iMac repair is the right place.

MacBook slow and hot – the fan runs constantly

"Gets hot and then slow", "the fan runs all the time": heat slows things down, and in our experience the system then reduces performance to protect itself. Check in Activity Monitor ("CPU" tab) whether a process is causing constant load. The MacBook Air with an M1 to M5 chip has no fan, and a warm case under load is normal there. If the fan of a MacBook Pro keeps running at high speed without any visible load in Activity Monitor, the MacBook belongs in the workshop. There, these devices needed an internal cleaning, a repair on the logic board or top case, or a heat-sink replacement. How much heat is normal and when it is a warning sign is explained in MacBook running hot?

MacBook storage full? Clean it up yourself in five steps

On M-chip Macs, the CPU and GPU share the same memory (unified memory). When RAM runs short, macOS keeps moving memory contents out to the SSD – this is called swapping. For that, the system needs free space on the SSD. When the drive is nearly full, this very mechanism gets squeezed: the system stalls, apps launch slowly and the beachball spins. On top of that, in our experience, the SSD itself performs worse when it has hardly any free space left. As a rule of thumb, keep at least 10–15% of your storage free – more on small SSDs (256 GB).

Step 1: Check storage usage and swap

• Open System Settings → General → Storage. You will see how full the SSD is and which categories take up the space. macOS also suggests what you can offload or delete.
• In Activity Monitor (Applications → Utilities), the "Memory" tab shows "Swap Used" at the bottom and the "Memory Pressure" graph. According to Apple, green means the Mac is using its memory efficiently, yellow means it will need more soon, and red means it needs more now. Several gigabytes of swap combined with a nearly full SSD is the classic sign of a throttled M-chip Mac.

Step 2: The usual space hogs

• Downloads folder – installers and old ZIPs pile up unnoticed.
• Old device backups – select the connected device under "Locations" in Finder, click "Manage Backups…" in the General tab and delete outdated backups.
• Mail attachments and Messages history – years of chat attachments often take up tens of gigabytes.
• Photos library – check whether "Optimize Mac Storage" is enabled in Photos settings.
• Leftovers from uninstalled apps – dragging apps to the Trash leaves caches and support files behind.

Then empty the Trash: nothing is really deleted until it is gone from there too.

Step 3: Clean out your login items

Everything listed under System Settings → General → Login Items (in newer macOS versions "Login Items & Extensions") launches automatically at every boot – each entry costs startup time and keeps running in the background afterward. Over the years, updaters, helpers and long-forgotten apps pile up there. Remove everything you do not use daily with the Remove button (the minus sign below the list), and go through the "Allow in the Background" list (in newer macOS versions "App Background Activity") as well.

Step 4: Two free tools we recommend

You do not need to buy anything for a thorough cleanup – two free programs are enough:

• OnyX (Titanium Software): the classic with a graphical interface. Clears system and app caches, runs maintenance scripts and rebuilds databases. Important: download exactly the version that matches your macOS release – the website shows clearly which version goes with which release.
• Mole (open source on GitHub): a terminal tool for a deeper cleanup. Once Mole is installed with brew install mole, mo clean clears deep-seated caches and mo uninstall removes apps along with all leftover files.

Step 5: If it is not the storage – safe mode and Apple Diagnostics

If plenty of space is free and the MacBook is still slow, first check Activity Monitor ("CPU" tab) for a process under constant load – that points to a software problem. After a macOS update or a data migration, Spotlight may also need to finish indexing first. That can take a day or two and resolves itself. Safe mode is the next test: according to Apple, macOS then loads no login items and only the extensions it needs, checks the startup volume and clears some system caches. Intel: hold the Shift key while powering on until the login window appears. Apple Silicon: hold the power button until the startup options appear, select the startup volume, then hold the Shift key and click "Continue in Safe Mode". If the Mac runs fast in safe mode, the slowdown comes from software that loads during a normal start. A restart ends safe mode. Finally, Apple Diagnostics shows whether a hardware component could be defective. On Apple Silicon, hold the power button until the startup options appear, then hold Command (⌘) + D. On Intel Macs, hold D while powering on. If the MacBook is still sluggish after that, it is time for the free diagnosis.

What is really behind "slow" in the end – experience from the workshop

The overview shows what ended up on the cost estimate for "slow" and what that usually costs. The figures come from our workshop with 20,000+ repairs since 2015, walk-ins in Hamburg and mail-ins combined. In the free diagnosis, we check the storage, drive, battery and temperatures and find out whether software or hardware is slowing the Mac down.

All prices in euros incl. VAT. Diagnosis and shipping are free.

How it breaks down: most often it was the drive (a new SSD or recovering the data from the old hard drive, almost always on an Intel model), then a repair on the logic board, and less often a cleaning, a reinstall or the battery. The self-check alone usually solves full storage, login items and a single process under constant load.

Intel or Apple Silicon makes the biggest difference here. Almost all devices that ended up with a workshop finding were Intel models: hard drive or SSD, logic board, cleaning, firmware. The most common cause we see on MacBooks with an M1 to M5 chip is full storage. A logic-board finding occurs there too, but it is not the first suspect.

What this means for your data: on all MacBooks with Apple Silicon, on Intel models with the T2 chip (2018 to 2020) and on the MacBook Pro with Touch Bar from 2016 and 2017, the SSD is soldered to the logic board. On older Intel MacBooks (up to 2015, MacBook Air up to 2017), it is usually a plug-in module. The usual response to a fault on the board is to replace the whole board. Where possible, we repair the board at component level, so the SSD with your system and data stays exactly where it is. With an SSD upgrade in an older Intel MacBook, we migrate your data to the new SSD. If the old hard drive already shows errors, securing the data comes first – if in doubt, through data recovery.

Three cases from the past few months

• MacBook Pro 13" (2012, Intel) – SSD upgrade with more RAM and a fresh macOS (walk-in from Farmsen-Berne): the customer decided against selling the device and wanted to keep using it. The cost estimate listed the upgrade: a 480 GB SSD, 8 GB of RAM and a fresh macOS. €340.
• MacBook Pro 15" (2017, Intel) – battery replacement and logic-board repair (walk-in from the Neustadt): came into the workshop throttled and sluggish, and the battery was already suspected at intake. On the bench, it turned out that the old battery was disconnected and the logic board accepted only 5 volts. The result: a battery replacement at the fixed price and one component replaced on the board – €420 in total.
• MacBook Pro 16" (2019, Intel) – heat-sink replacement (mailed in from the Germersheim district): according to the fault description, the device became extremely slow when warm, and the audio stuttered in the DJ software. The customer had already tried cleaning the fans and reinstalling the system. The cost estimate listed the heat sink, which was replaced – €140.

All prices in euros incl. VAT.

Special cases

Does more RAM help? Not on M-chip Macs

On M-chips, the memory is part of the chip package and cannot be upgraded. So the fix is to free up storage, and to choose more RAM and a larger SSD for your next purchase. The earlier 8 GB base models in particular swap heavily in everyday use and are therefore the most sensitive to a full SSD. Apple itself says that free or unused memory does not necessarily mean better performance – what matters is memory pressure (step 1). On older Intel MacBooks, an upgrade is often still possible. What applies to your model is listed under MacBook upgrades.

Only one app is slow – browsers and old Intel apps

"The browser hangs", "only one app is slow": dozens of tabs, high-resolution streaming or a single stuck app create constant load. Activity Monitor ("CPU" tab) shows the culprit, and quitting or updating it usually helps. On a Mac with Apple Silicon, old Intel apps run through Rosetta, and Apple recommends the Apple Silicon version for the best performance. The Finder's Get Info window (⌘ + I) shows whether an app is affected: look for "Kind: Application (Intel)". When such a device stayed sluggish anyway, the logic board ended up on the workshop's cost estimate for this symptom too.

If nothing has helped

If there is enough free storage, the list of login items is short and the MacBook is still slow, it belongs in the workshop. On Intel models, that most often meant the drive (a new SSD or data recovery from the old hard drive), then the logic board, and less often a cleaning, a reinstall or the battery. The diagnosis is free, even if you decide against the repair afterward: you get a fixed price and know what is slowing things down. In Hamburg-Altona, drop it off in person (no appointment needed). From the rest of Germany, mail it in free of charge via DHL. We give a 12-month warranty on every repair. All prices by repair type: What does a MacBook repair cost?