Delivery Optimization Files: What They Are and Whether to Delete Them

Updated: November 2026

Disk Cleanup flags several gigabytes of "Delivery Optimization Files" on a laptop that's out of space, and someone has to decide whether ticking that box breaks anything. It doesn't, and this guide covers the three ways to clear the files, how big the cache is allowed to grow, and the peer-to-peer settings that decide how often you'll see it again. The last part is about the fleet, where the same cache stops being a disk problem and becomes a bandwidth tool.

TL;DR

• What they are. Cached update and app files a PC keeps so nearby PCs can download from it.
• Safe to delete. Yes, Windows re-downloads anything it still needs.
• Fastest way. Disk Cleanup, Settings, or Delete-DeliveryOptimizationCache -Force in PowerShell.
• Default limits. Up to 20% of free disk space, with each file expiring after three days.
• Fleet control. Download mode, cache size and bandwidth caps, set by Group Policy or Intune.

What Are Delivery Optimization Files?

Delivery Optimization is the downloader Windows uses for its own content. Microsoft's Intune team calls it "an HTTP downloader with built-in peer-to-peer capabilities" in its August 2026 configuration guide. It pulls Windows updates, Microsoft 365 Apps updates, Defender definitions, Store apps and Intune Win32 apps.

The files are its cache. Once a PC downloads an update, it keeps the pieces for a while so other PCs on the same network can fetch them locally instead of from Microsoft. That's peer-to-peer caching, and it's on out of the box. Per Microsoft's Delivery Optimization reference, the default download mode is LAN (1), which shares with peers behind the same public IP.

Not every PC joins in, and not every file gets shared. By default a device needs 4 GB of RAM and a 32 GB disk to peer, and only files of 50 MB or more are cached for sharing. So the cache is mostly cumulative updates, feature updates and big app packages.

The cache lives on the system drive. To see the exact folder on a given PC, run (Get-DOConfig).WorkingDirectory in PowerShell.

Are Delivery Optimization Files Safe to Delete?

Yes. The cache holds copies of content that's already been downloaded. Deleting it doesn't uninstall an update, doesn't roll anything back, and doesn't touch the files Windows Update needs for the next install. If Windows still wants something, it downloads it again.

There are two small costs. A PC with an empty cache stops serving its neighbors until it downloads something new. And if a download is in progress when you clear the cache, it starts over. Clear it when Windows Update isn't mid-download and neither cost matters.

Here's the part that saves time: the cache already cleans itself. Each file expires after 259,200 seconds (three days) by default, and the cache is capped at 20% of available disk space. A big number in Disk Cleanup is usually last Tuesday's cumulative update sitting out its three days. Deleting it buys space for now. If one model of laptop keeps hitting this, the fix is the cache policy further down, not a weekly cleanup ticket.

How to Delete Delivery Optimization Files

Three ways, same result. Pick the one that fits how many PCs you're touching.

Disk Cleanup

Run cleanmgr, pick the C: drive, tick Delivery Optimization Files and click OK. If you're already in there, Windows Update Cleanup under "Clean up system files" is usually the bigger win, and old upgrade leftovers are often bigger still (see how to delete Windows.old for that one).

Settings

On Windows 11, go to Settings > System > Storage > Temporary files, tick Delivery Optimization Files and click Remove files. Windows 10 has the same option under Settings > System > Storage. While you're in Settings, Windows Update > Advanced options > Delivery Optimization > Activity monitor shows how much this PC downloaded from Microsoft, from local peers, and uploaded to others this month.

PowerShell

PowerShell is the one that scales, because the same lines run through any RMM. Check before you delete:

powershell
# Where the cache lives and how big it is
(Get-DOConfig).WorkingDirectory
Get-DeliveryOptimizationPerfSnap | Select-Object Files, CacheSizeBytes, AvailableDiskBytes

# Clear it without a prompt (Windows 10 1903 and later)
Delete-DeliveryOptimizationCache -Force

# Also remove files someone pinned in the cache
Delete-DeliveryOptimizationCache -IncludePinnedFiles -Force

All three cmdlets are documented on Microsoft's Monitor Delivery Optimization page. Run them elevated.

How Big Can the Delivery Optimization Cache Get?

Six policies decide the size and lifetime of the cache. Defaults below are from Microsoft's reference, checked 9 November 2026.

The percentage is of free space, not total disk. Microsoft's own example: set 10% on a device with 100 GB free and the cache can use up to 10 GB. On the 20% default, that same device can hold 20 GB.

There's a trade-off in every row. A short cache age and a small cap keep disks clear but leave fewer peers holding the update when the rest of the office asks for it. The Intune team's guide recommends 14 days of cache age (1,209,600 seconds) and 20% to 30% cache size for standard offices. That's the peering-friendly end. For 128 GB laptops, an absolute cap in GB is the safer setting, because a percentage of a nearly full disk swings around.

Peer-to-Peer Settings by Group Policy and Intune

In Group Policy, everything sits under Computer Configuration > Administrative Templates > Windows Components > Delivery Optimization. In Intune, Microsoft recommends the Settings Catalog (search "Delivery Optimization") over the older template, so settings from different profiles don't conflict.

Download mode is the setting that matters most:

Microsoft's reference calls Group mode "the recommended option for most organizations looking to achieve the best bandwidth optimization." For an MSP, Group mode with one Group ID per client site is the clean setup: peers share inside a client, never across clients. If devices move between offices, set DOGroupIdSource to 3 and hand out the Group ID with DHCP option 234.

Two defaults surprise people. Peering is off when a VPN is detected, so remote staff download straight from Microsoft. And devices don't upload to peers while on battery unless you set DOMinBatteryPercentageAllowedToUpload (Microsoft suggests 40%).

If you want to watch someone build this in the Settings Catalog, this walkthrough covers the settings above in about 14 minutes.

Turning Delivery Optimization off entirely is a different job from controlling it. If the real goal is pausing updates, see how to stop Windows Update without breaking Defender.

Delivery Optimization and Fleet Bandwidth

On one PC, Delivery Optimization files are a disk-space line item. Across a fleet, they're the reason Patch Tuesday doesn't flatten a client's internet link.

Microsoft's Intune team puts the math plainly: a 1 GB cumulative update pushed to 10,000 devices is 10 TB of internet traffic without peer sharing. Scale it down to a 40-seat client office on one WAN link. In HTTP-only mode, that's 40 GB down the pipe on the same morning. With LAN or Group peering, the first devices pull from Microsoft and the rest pull from them, so in the best case only about 1 GB crosses the WAN.

The bandwidth policies cap the HTTP side of that traffic:

• DOMaxBackgroundDownloadBandwidth. A hard cap in KB/s, the better choice for slow links per Microsoft's reference.
• DOPercentageMaxBackgroundBandwidth. A percentage of available bandwidth for background downloads.
• DOSetHoursToLimitBackgroundDownloadBandwidth. Different limits inside and outside business hours.

The Intune team's guide suggests 10% to 25% for background downloads during business hours at hub-and-spoke branches. These caps apply to downloads from Microsoft, Connected Cache and internet peers. Downloads from LAN peers aren't throttled by them, which is the point.

Two more pieces round it out. A small seeder ring (the guide suggests 5% to 10% of devices) gets the update first and fills the caches before the broad ring asks for it. And at sites with more than about 100 devices, Microsoft Connected Cache gives peers a permanent local source to fall back on.

This is also why WSUS shutting down matters to bandwidth, not just to patch approval. When Microsoft deprecated WSUS in September 2024, r/sysadmin's thread on it passed 1,000 upvotes, and Delivery Optimization came up as the half-joking answer to "so what caches updates now?"

To see whether peering is working, measure it. Get-DeliveryOptimizationPerfSnapThisMonth shows bytes from peers against bytes from HTTP for the current month, and the Windows Update for Business Delivery Optimization report shows the same across devices for the last 28 days. Run the PerfSnap line as a scheduled script across every client site (in OpenFrame, the RMM you already use, or anything that runs PowerShell) and a site where peers deliver nothing stands out on the first pass. Pair it with how to check bandwidth usage when a client says the internet is slow every second Wednesday.

The Short Version

Delivery optimization files are safe to delete, and Windows deletes them itself after three days anyway. Clear them with Disk Cleanup on one PC or Delete-DeliveryOptimizationCache -Force on many. If the same devices keep filling up, set an absolute cache cap instead of cleaning by hand.

Across a fleet, treat the cache as a bandwidth tool. Group mode with a Group ID per client site, a business-hours background cap and a small seeder ring turn one big download per device into one per site.

Next, check what else is eating the disk. After a feature update, Windows.old usually dwarfs the Delivery Optimization cache, and the Windows.old guide linked above shows how to clear it safely.