Is it safe to delete the SoftwareDistribution folder?

Yes, it's safe to delete the contents of C:\Windows\SoftwareDistribution\Download, as long as you stop Windows Update first. That folder only holds update files waiting to be installed or already used. If Windows still needs any of them, it downloads them again. Deleting the whole SoftwareDistribution folder is also safe, it's part of Microsoft's own troubleshooting steps, but you lose your update history list.

Quick verdict:

• Download: safe to empty once the update services are stopped.
• DataStore: safe to remove when you're fixing Windows Update, but the update history in Settings goes with it.
• The whole folder: safe to delete or rename, Windows recreates it.
• Don't do it in the middle of an update, or while Windows is waiting to restart to finish one.

What is the SoftwareDistribution folder?

C:\Windows\SoftwareDistribution is the working folder of the Windows Update service (wuauserv). It has a few subfolders, and two matter here:

• Download: the update packages Windows Update has downloaded, usually through the Background Intelligent Transfer Service (BITS). Cumulative updates, driver updates, Microsoft Defender definitions and feature update files can all pass through here.
• DataStore: a small database (DataStore.edb) and logs that Windows Update uses to keep track of updates it has seen and installed. This is where the list in Settings → Windows Update → Update history comes from.

The folder grows when updates download, and normally shrinks again as they're installed and cleaned up. It tends to stay large when an update keeps failing, because the same package sits there, half used.

How much space does it use?

The quickest check: open File Explorer, go to C:\Windows\SoftwareDistribution, right-click Download and choose Properties. Windows may ask for administrator permission to open the folder.

To compare it with the rest of the drive, scan C: or C:\Windows with SquirrelDisk and click through to SoftwareDistribution. SquirrelDisk runs without administrator rights, so parts of system folders your account can't read are skipped and may look smaller than they are. Also note that SquirrelDisk never deletes anything inside C:\Windows: you can see the size there, but the cleanup has to be done with the Windows tools below.

How to delete it safely

Start with Disk Cleanup and the troubleshooter

If the goal is space rather than a broken update, try the built-in tools first:

1. Open Disk Cleanup (press Start, type it), pick C:, then click Clean up system files.
2. Tick Windows Update Cleanup and Delivery Optimization Files, and click OK.

Be aware that Windows Update Cleanup mostly removes old, replaced updates kept in the Windows component store (WinSxS), not the Download folder itself. Microsoft describes it as a way to reduce the size of the component store. It's often the bigger win, so it's worth running anyway.

If an update is stuck, run the Windows Update troubleshooter from Settings → System → Troubleshoot → Other troubleshooters first. It resets the components that need it.

Empty the Download folder

1. Make sure no update is installing, and restart if Windows says a restart is pending.

2. Right-click Start and open Terminal (Admin).

3. Stop the update services:

   net stop wuauserv
   net stop bits
   

4. In File Explorer, open C:\Windows\SoftwareDistribution\Download, select everything inside it and delete it. Keep the Download folder itself.

5. Start the services again:

   net start wuauserv
   net start bits
   

6. Open Settings → Windows Update and click Check for updates.

If a service starts again by itself before you delete the files, just run the stop commands once more.

Reset the whole folder (to fix Windows Update)

This is for updates that keep failing, not for routine cleanup. Microsoft's reset steps for Windows Update do exactly this. The cautious version renames instead of deleting:

net stop wuauserv
net stop bits
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
net start bits
net start wuauserv

Windows creates a fresh SoftwareDistribution folder. Once updates install normally again, delete SoftwareDistribution.old (stop the services first if Windows says a file is in use). Microsoft's shorter version removes the folder straight away with rd /s /q %systemroot%\SoftwareDistribution.

What you should not delete

• Anything during an update. If Windows is downloading, installing, or waiting for a restart to finish an update, let it finish first. Removing files halfway can make that update fail and start again.
• DataStore, if you care about the history. Deleting it doesn't uninstall anything, but the Update history list in Settings may come back empty or short. The updates themselves stay installed, and you can still remove one from Update history → Uninstall updates.
• C:\Windows\WinSxS. It's a different folder and must not be deleted by hand. Microsoft warns that doing so can leave your PC unable to boot or update. Use Disk Cleanup instead.
• C:\Windows\System32\catroot2. Microsoft's reset steps rename it only as a later troubleshooting step, not for space.

If updates fail after a cleanup, run the Windows Update troubleshooter, restart, and check for updates again. If you renamed the folder, you can stop the services, delete the new one and rename SoftwareDistribution.old back.

Better ways to free space

SoftwareDistribution is rarely the biggest folder on a full drive. After a feature update, the previous Windows installation usually is: see is it safe to delete Windows.old. Delivery Optimization keeps its own cache too, covered in Delivery Optimization files. For everything outside the Windows folder, a scan with SquirrelDisk shows which folders take the space, so you can decide what to remove.