Slow PC startup: the real causes and how to fix them

A slow PC startup is almost always caused by programs that launch automatically with Windows. Next come a mechanical or nearly full hard drive, and updates waiting for a real restart. These causes can be checked in a few minutes, and most can be fixed without uninstalling anything.

The desktop appears, but the computer stays unusable for several minutes: the cursor spins, windows open in slow motion. That's often where the feeling of a 'tired' PC comes from. In reality, Windows is simply launching a lot of things at the same time.

1. Do a real 'Restart' (not 'Shut down') to finish pending updates.
2. Disable unneeded startup programs in Task Manager (Ctrl + Shift + Esc).
3. Check that at least 15% of the C: drive is free.
4. If the computer still has a mechanical hard drive, an SSD cuts startup time by three or more.

On a PC with an SSD, the desktop should appear within 10 to 30 seconds, and the computer should be usable less than a minute later. With a mechanical hard drive, 1 to 3 minutes is nothing unusual. Beyond 3 to 5 minutes before you can work, there's clearly a cause to find.

Note the difference between the two stages: if the screen stays black or shows the manufacturer's logo for a long time, the hardware stage (the BIOS) is dragging; if it's after the desktop appears, it's the programs and Windows itself.

1. Too many startup programs

Every installed program wants to 'start with Windows': chat apps, game launchers, printer tools, update assistants, cloud storage. One by one they're light; together, they fight over the disk and memory at the very moment the computer needs them most. Beyond about ten, the effect is clearly noticeable.

2. A 'fast startup' that isn't really one

With Windows fast startup, enabled by default, 'Shut down' doesn't fully close the system: Windows goes into partial hibernation to start faster next time. It works, but small glitches accumulate from day to day, since nothing is ever truly reset. Only 'Restart' starts from a clean slate.

3. A mechanical or nearly full hard drive

Starting up mostly means reading thousands of small files. A spinning hard drive does this slowly, and a nearly full drive leaves Windows less room to work. Below 10% free space, everything slows down, startup included. A hard drive that is starting to fail also lengthens startup, sometimes long before it breaks down.

4. Updates waiting to finish

An update that's installed but not yet finalised can resume its work at every power-on, as long as the computer hasn't been truly restarted. Startup then feels slow, day after day.

5. Background update programs

Many programs install their own update service (browsers, office suites, PDF readers, manufacturer software). They don't always appear in the startup apps list, because they run as services or scheduled tasks, and they all wake up at startup to check for a new version.

6. A heavy antivirus, or two antiviruses

An antivirus scans files as they're opened, so massively at startup. Some third-party antiviruses are much heavier than Microsoft Defender, which is built in and sufficient for everyday use. Two antiviruses running at the same time get in each other's way and slow startup down considerably.

7. A device or connection that keeps Windows waiting

An external drive, a forgotten USB stick, a network printer or a network drive to reconnect can make Windows wait several seconds or more while you sign in. Unplugging non-essential devices lets you check this in a single restart.

1. Open Task Manager (Ctrl + Shift + Esc), then the 'Startup apps' tab ('Startup' on Windows 10).
2. At the top right, 'Last BIOS time' shows how long the hardware stage took. Beyond 15 to 20 seconds, look at the BIOS or connected devices rather than Windows.
3. The 'Startup impact' column ranks each program from 'Low' to 'High'. Start with high-impact programs you don't use every day.
4. Right-click and choose 'Disable'. The program stays installed and works normally when you open it yourself: it just no longer launches on its own.
5. In the 'Performance' tab > 'Disk', check the type (SSD or HDD) and, in File Explorer, the free space on the C: drive.
6. Restart ('Restart', not 'Shut down') and compare.

For a precise measurement, Windows records the duration of every startup in Event Viewer: log 'Applications and Services > Microsoft > Windows > Diagnostics-Performance > Operational', event 100. Events 101 to 110 in the same log name the programs and drivers that slowed startup down.

• Startup programs: disable them in Task Manager, or in Settings > Apps > Startup.
• Fast startup: choose 'Restart' at least once a week. If glitches keep coming back, turn it off: Control Panel > Power Options > 'Choose what the power buttons do'.
• Full drive: Settings > System > Storage, then 'Cleanup recommendations'. Keep at least 15% free.
• Mechanical hard drive: a 500 GB SSD costs about €40 to €70, plus €40 to €80 of labour if you have it installed. It's the best possible upgrade for a slow startup.
• Pending updates: Settings > Windows Update, install everything left, then 'Restart'.
• Third-party update services: uninstall software you no longer use; it's the safest way to remove its update service.
• Antivirus: keep only one. Microsoft Defender is enough for most home use.
• Devices: unplug external drives and USB sticks before powering on, and remove network drives that no longer exist.

• Your antivirus, including Microsoft Defender.
• Manufacturer drivers and utilities for the keyboard, touchpad or sound, if you don't know what they do.
• Programs you genuinely need right after startup (a work messaging app, for example).

When in doubt, disable one program at a time: it's reversible in one click in the same list. Be wary of 'startup booster' software: Windows already provides everything you need, for free.

• Startup gets longer week after week for no reason, with clicking noises: a failing hard drive. Back up your files without waiting.
• Windows shows 'Preparing Automatic Repair' at every power-on: system files are probably damaged.
• The screen stays black or stuck on the manufacturer's logo for several minutes: the problem is before Windows (hardware or BIOS), and a professional opinion is useful.

Nyctale counts the programs launched at startup, checks whether the computer has truly restarted recently or only been 'shut down' with fast startup, and checks free space and drive health. It tells you which of these is slowing your startup, and opens the right list directly so you can act.

To measure what really slows startup, the free diagnostic tools, Autoruns in particular, go further than Task Manager. And if startup fails with a blue screen, see our dedicated guide.