Windows Update Stuck Downloading at 0% or 100%? How to Unstick It

You open Settings → Windows Update, an update starts downloading, and the percentage freezes — stuck at 0%, or pinned at 100% without ever installing.

Why: a frozen download is almost never a corrupted update. The usual causes are the Windows Update services losing their connection mid-transfer, not enough free disk space to stage the package, or a damaged download cache (the SoftwareDistribution folder). A stuck percentage is a symptom of one of those — so you work through them fastest-first.

Fix 1: Restart, then re-check disk and connection

Microsoft’s first recommendation for a stuck download is the simplest one, because a reboot clears any app that’s silently blocking the update.

1. Save your work and restart the PC (Start → Power → Restart — not Shut down).
2. After it comes back, confirm you have free space. Microsoft says you need at least 20 GB free for a 64-bit version of Windows (16 GB for 32-bit) to stage an upgrade. Open Settings → System → Storage and clear space if you’re tight.
3. Confirm you’re actually online: Settings → Network & internet → Wi-Fi (or Ethernet) should show Connected.
4. Go back to Settings → Windows Update and select Check for updates so the download restarts cleanly.

Fix 2: Run the Windows Update troubleshooter

The built-in troubleshooter resets the update components for you and is the official next step.

1. Select Start → Settings → System → Troubleshoot → Other troubleshooters.
2. Under Most frequent, select Run next to Windows Update.
3. Follow the on-screen prompts, then restart the device when it finishes.
4. Return to Settings → Windows Update → Check for updates.

Fix 3: Reset the download cache manually

If it’s still frozen, the staged download is likely corrupt. Clearing the SoftwareDistribution and catroot2 folders forces Windows to fetch a fresh copy. Open an elevated Command Prompt (right-click Start → Terminal (Admin)) and run:

net stop bits
net stop wuauserv
net stop cryptsvc
ren %systemroot%\SoftwareDistribution SoftwareDistribution.old
ren %systemroot%\System32\catroot2 catroot2.old
net start bits
net start wuauserv
net start cryptsvc

Reboot, then Check for updates again. Windows rebuilds those folders automatically; you can delete the .old ones once updates work.

FAQ

It says 100% but never installs — is that different? Usually no. The download finished but staging or the pre-install step stalled. A restart followed by Check for updates clears most of these; if not, run Fix 2 then Fix 3.

How long should I wait before calling it stuck? Large feature updates can genuinely sit at one number for several minutes. If the percentage hasn’t moved in 30+ minutes and the disk light is idle, treat it as stuck and start with Fix 1.

Sources: Microsoft Support — Troubleshoot problems updating Windows, Microsoft Learn — Additional resources for Windows Update (reset components)