Windows performance

Windows storage almost full and computer running slow

When your main drive gets close to full, Windows has less room to manage temporary files and virtual memory, which can slow the whole system down noticeably.

Difficulty
Easy
Time
20–45 minutes
DIY cost
$0–$80
Pro cost
$60–$120

Symptoms

  • Windows shows a low disk space warning
  • System feels sluggish, especially when opening or saving files
  • Updates fail or won't download
  • Storage graph in Settings shows the drive nearly maxed out

Likely causes

  • CommonLarge media files (videos, photos) accumulating over timeThese take up disproportionate space compared to documents or apps.
  • CommonOld downloads and installer files left in the Downloads folderInstallers and duplicate downloads are easy to forget about.
  • CommonWindows temporary files and old update leftoversThese build up silently and can total several gigabytes.
  • PossibleToo many installed programs, some rarely usedLarge apps (games, creative software) can each use tens of gigabytes.
  • PossibleA small drive (like 128–256GB) that was always tight for your usageSome laptops ship with limited storage relative to typical use.

What to do

  1. Open Settings > System > Storage to see a breakdown of what's using space.
  2. Use Storage Sense (in the same Settings page) to automatically clear temporary files and old Recycle Bin items.
  3. Go through your Downloads folder and delete installers and files you no longer need.
  4. Uninstall large programs and games you no longer use from Settings > Apps.
  5. Move photos and videos to an external drive or cloud storage if you don't need them locally.
  6. Run Disk Cleanup and check 'Previous Windows installation(s)' if present, which can free many gigabytes after an upgrade.
  7. Empty the Recycle Bin once you've reviewed what's in it.
  8. If you're consistently near full even after cleanup, consider a larger drive or offloading files to cloud/external storage long-term.

Tools and parts

  • None required
Larger internal SSD or external driveSearch: “internal SSD upgrade for [your device] / portable external hard drive”

When to call a pro

If you need more storage than cleanup can provide and aren't comfortable upgrading the drive yourself, a shop can install a larger one and migrate your data.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.