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Measure and Fix a Slow Windows Boot

Find out where the seconds go - firmware, driver init or startup apps - before disabling anything. Windows keeps the numbers in the event log.

by@guidox updated:10/30/26 time:20 min level:Intermediate tested on:Windows 11 24H2, NVMe boot drive works on:Windows 10, Windows 11
TL;DR

Read **Diagnostics-Performance** event 100 in Event Viewer for the boot duration and the apps that slow it down, then fix the top entry. Disabling random services is not a method.

Before you start

Requirements

  • Windows 10 or 11
  • Admin rights
  • A stopwatch or the event log
Step by step

Instructions

01

Measure the baseline

Reboot three times and time from the power button to a usable desktop, with the same apps. One measurement is noise; three show the real figure.

02

Read the boot report

Open **Event Viewer > Applications and Services Logs > Microsoft > Windows > Diagnostics-Performance > Operational** and look for event 100. It lists the boot duration and the slowest startup items with their times.

eventvwr.msc
Diagnostics-Performance > Operational > Event ID 100
tipEvent 101 lists slow shutdowns, event 102 slow app starts. Same log, different question.
03

Cut startup apps at the source

Use **Settings > Apps > Startup** and disable what you do not need at login. Better still, uninstall what you do not need at all - the app then stops re-adding itself.

⚠ warningTask Manager's Startup tab shows the same list. Disabling an entry does not stop a scheduled task from starting it later.
04

Check the delay, not only the count

Event 100 often points at one item with a multi-second delay. A single slow antivirus scan or a network drive mapping costs more than ten small tray apps.

05

Deal with the network wait

A mapped drive on a NAS that is not awake holds the desktop for its timeout. Set **Always wait for the network at startup** off in the group policy, or map the drive after login.

gpedit.msc > Computer Configuration > Administrative Templates > System > Logon
06

Think about the storage

If the boot is slow before Windows even starts - logo for a long time - the firmware is waiting for a device. Unplug USB drives and check the boot order before blaming Windows.

tipAn NVMe drive at 100% health boots in seconds. A nearly full SATA SSD can take a minute.
Troubleshooting

Common issues

There is no event 100

The log is disabled or the machine uses fast startup with resume instead of boot. Power off fully once with shutdown /s /t 0 and check again.

Boot is fast but the desktop is not ready

Startup apps are the delay, not the boot. Work through the startup entries in event 100.

It takes minutes before the logo appears

Firmware-level: USB devices, a failing drive or memory training. Unplug peripherals and check the POST timing.

It got slower after an update

A new startup task or a driver. Compare event 100 before and after the update date.

FAQ

Frequently asked

Is fast startup worth it?

It shortens the time to the login screen but can cause driver oddities. With an NVMe drive the gain is small.

Do I need a registry cleaner?

No. The measured delays come from apps and drivers, not from registry entries.

How to undo this

Re-enable the startup entries you disabled in **Settings > Apps > Startup** and restore the logon policy if you changed it. Nothing is deleted permanently.

Changelog · 1 entry
  1. 2026-10-30
    First version
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