Are Windows Temporary Files Safe to Delete?

You open Settings → System → Storage → Temporary files, see a checklist with a size next to each entry, and the obvious move is to tick everything and click Remove. Most of the time that works out fine.

Occasionally it does not, because Microsoft put two things on that list which are not temporary in any sense a person would recognise. One of them is your Downloads folder.

Here is what every entry on that screen actually is, which ones regenerate harmlessly, and the two to think about before ticking.

The full checklist

Sizes vary enormously by machine; the ranges below are typical on a system a year or two into use.

The two that are not temporary

Downloads

This is the one that catches people. The Downloads entry deletes the entire contents of C:\Users\[you]\Downloads — every installer, PDF, spreadsheet, photo and zip you have ever saved from a browser.

Microsoft’s reasoning is that Downloads is a transit folder. In practice it is where a large number of people keep working documents, invoices, software they paid for, and the only copy of things emailed to them.

It is unticked by default, and it should stay that way until you have opened the folder and looked. Sort by size, move what matters somewhere sensible, and then decide.

The more dangerous version of this is in Storage Sense, which can do it on a schedule with no prompt at all. Go to Settings → System → Storage → Storage Sense and check Delete files in my Downloads folder if they have not been opened for more than. Set it to Never unless you have a genuine reason not to. Left at 30 days, it quietly removes things you meant to keep.

Recycle Bin

Emptying the bin does genuinely free space — until you empty it, deleted files still occupy the disk, and by default the bin can hold up to around 5% of the drive. On a 1TB drive that is 50GB of files you thought were gone.

But it is also your last undo. Once the bin is emptied, recovery means file recovery software and a lot of luck.

Open it, sort by Date deleted, and scan the last week or two before you clear it. That takes thirty seconds and occasionally saves a bad afternoon.

The ones that are genuinely safe

Windows Update Cleanup removes superseded components from the update store. After it runs you can no longer uninstall the updates it cleaned up, which matters only if a recent update broke something. On a stable machine this is one of the better wins, typically several gigabytes.

Delivery Optimisation files are copies of update packages Windows cached so it could share them with other PCs on your network. Deleting them costs nothing; Windows re-downloads whatever it needs.

Thumbnails is the preview image cache Explorer builds for photos and videos. Clearing it means folders of images render their previews slowly once, then behave normally. It is also the fix for thumbnails displaying the wrong picture.

DirectX Shader Cache holds compiled GPU shaders. Games will stutter slightly on first launch while they recompile, then return to normal. Clearing it is a standard step when a game has graphical glitches after a driver update.

Windows error reports are crash logs queued for Microsoft. Unless you are mid-way through diagnosing a specific crash with support, remove them.

Device driver packages keeps older versions of drivers you have updated. It is safe in almost all cases, with one exception: if you updated a graphics or chipset driver in the last few days and are not yet sure it is stable, leave this one for a week so rolling back stays easy.

Previous Windows installation(s) is Windows.old and deserves its own consideration — it is your rollback path for ten days after a feature update. There is a full walkthrough in can you safely delete Windows.old.

Disk Cleanup still exists and shows a little more

The older tool reaches a couple of entries the Settings page does not surface.

1. Press Win+R, type cleanmgr, press Enter.
2. Pick the C drive and click OK.
3. Click Clean up system files — without this step the system-level entries including Previous Windows installation(s) never appear.
4. Select C again, wait for the rescan, tick what you want, click OK.

The More Options tab also offers to remove all but the most recent System Restore point, which can free a surprising amount. That one is irreversible — you lose every older restore point permanently — so only use it when you are confident the machine is currently healthy.

Clearing Temp folders by hand

Occasionally the Settings cleanup leaves a large Temp folder behind, because Windows skips files that are currently open. If you want to be thorough:

• Paste %LOCALAPPDATA%\Temp into the Explorer address bar, select all, delete.
• Do the same with C:\Windows\Temp.

Windows will refuse on a handful of in-use files. Click Skip and move on. Rebooting first reduces how many are locked.

Do not do this while an installer or a Windows update is running. Those processes stage files in exactly these folders and pulling them out mid-operation produces a failed install.

What not to do

• Do not tick Downloads without looking in the folder. This is the single most regretted click on that screen.
• Do not set Storage Sense to clean Downloads on a schedule unless you treat the folder as genuinely disposable.
• Do not empty the Recycle Bin reflexively when you are short on space. Scan it first.
• Do not delete folders inside C:\Windows by hand looking for more to clear. Use the supported tools; they know what is referenced.
• Do not install a “temp file cleaner” or registry cleaner. Everything on this page is built into Windows. The third-party tools add a background process, offer no additional reclaim, and registry cleaners in particular are capable of breaking an install for no benefit at all.
• Do not clean while updating. Let Windows Update finish and reboot first.

Realistic expectations

On a machine that has never been cleaned, the safe entries together typically return 5–15GB, and considerably more if Windows.old is present. It takes about five minutes.

Then turn on Storage Sense — weekly, or on low disk space — so you do not have to think about it again. With the Downloads rule set to Never, it is a safe thing to leave running.

If the drive fills up again regardless, something specific is growing and the cleanup list will not catch it. The detective work is in C drive full for no reason.