Windows Update Cache
Windows stores downloaded update payloads in SoftwareDistribution\Download while the Windows Update service stages cumulative updates, feature updates, servicing stack packages, Microsoft Defender definitions, and express update fragments. Those files can accumulate after installs, or become stale when a download is interrupted, leaving behind partially downloaded .cab, .msu, .psf, and ESD package data that Windows tries to reuse on the next scan or install. Kudu clears the cached update payloads in this download store without touching your personal files, accounts, saved passwords, or Windows settings.
Why clean Windows Update Cache?
- Interrupted or failed downloads leave partial .cab, .msu, .psf, or ESD files behind, and Windows Update may keep retrying the same bad payload while showing repeated download failures or updates stuck at a fixed percentage
- Superseded cumulative updates and express package fragments can remain in SoftwareDistribution\Download after newer builds are installed, wasting several gigabytes and showing up as unexpectedly low free space on the system drive
- Corrupted cached payloads can cause install loops where an update downloads, attempts to install, rolls back, and then reappears in Windows Update history as failed again
- When the download cache contains stale package metadata tied to an earlier scan, Windows Update can spend a long time checking or preparing updates and appear stuck on 'Downloading' or 'Installing' with little disk or network progress
- A damaged local copy of Defender definition packages can prevent security intelligence updates from applying cleanly, which users notice as repeated definition update failures in Windows Security or Settings
- Feature update staging files left from an abandoned upgrade can consume large amounts of space and trigger low disk space warnings, especially on smaller SSDs, even though the upgrade is no longer being installed
Cache paths Kudu targets
Windows
%WinDir%/SoftwareDistribution/Download |
Common questions about Windows Update Cache
Download Kudu and reclaim your disk space.
Available on Windows, macOS, and Linux. No account required, no feature gates, no telemetry without consent. All cleaning targets are open source and community-auditable.