Point CCleaner at One Drive Instead of Your System Drive

CCleaner's default behavior is to clean your C: drive (or whichever drive holds Windows). If you want to clean a different drive — a secondary hard drive, external USB drive, or network location — you need to change where CCleaner looks before it starts deleting. The process differs slightly between CCleaner Free and CCleaner Professional, but both let you pick your target.

The reason this matters: CCleaner finds temporary files, browser caches, and leftover installer fragments on whichever drive you point it at. If you point it at your data drive by mistake, it will clean that drive instead of your system drive. If you do not change the setting, it cleans C: by default, which is usually what you want — but not always.

Key Takeaways

  • CCleaner defaults to cleaning your C: drive; you must manually select a different drive before running the scan if you want to clean something else.
  • In CCleaner Free, you select the target drive in the Cleaner section under Custom Clean, before you click Analyze.
  • CCleaner Professional adds a Drives tab that lets you pick which physical drive to scan, making the process more direct.
  • External drives and USB sticks appear in the drive list only when they are plugged in and mounted; CCleaner will not find them if they are disconnected.
  • Always run Analyze first to see what CCleaner found on that drive before you click Run Cleaner, so you can confirm it is targeting the right location.

How to Select a Different Drive in CCleaner Free

Open CCleaner and go to the Cleaner tab on the left side. Under "Windows" and "Applications," you will see a list of file types that CCleaner can remove — Temporary Files, Recycle Bin, Recent Documents, and so on. Each one has a checkbox.

Look for the Custom Clean button or section. Click it to expand options for where CCleaner will search. You should see a dropdown or list showing available drives. Select the drive you want to clean from this list. Once you have selected it, click Analyze to scan that drive for the file types you checked. CCleaner will show you what it found. Review the results, then click Run Cleaner to delete those files from the selected drive.

If you do not see a Custom Clean section, your version of CCleaner may be older. Update it through Help > Check for Updates, or read the latest version from the CCleaner website.

Using the Drives Tab in CCleaner Professional

CCleaner Professional includes a dedicated Drives tab that makes selecting a target drive more straightforward. Open CCleaner Professional and click the Drives tab at the top. You will see a list of all connected drives — your C: drive, any secondary internal drives, external USB drives, and SD cards that are currently plugged in.

Click the drive you want to clean. CCleaner will highlight it and show you a preview of what it will remove from that drive. Click Clean to begin. The Professional version also lets you schedule automatic cleaning on a specific drive, which the Free version does not offer.

The Drives tab is the fastest way to target a specific drive if you have CCleaner Professional. If you have Free, use the Custom Clean method described above.

What Happens When You Clean an External or Secondary Drive

CCleaner treats external drives and secondary internal drives the same way it treats your C: drive — it looks for temporary files, cache, and installer leftovers. On an external drive, this usually means old browser cache files, Windows Update temporary files (if the drive was ever used as a Windows installation target), and process temp folders.

External drives must be plugged in and mounted before CCleaner can see them. If you unplug the drive, CCleaner will not list it. If you plug it back in, it will appear again. CCleaner does not clean drives that are not currently connected, so there is no risk of accidentally cleaning the wrong external drive if it is not plugged in.

One caution: if an external drive holds program files or process data (not just media or backups), cleaning it may remove files those programs need to run. Before you clean an external drive that holds installed software, back it up or run Analyze first to see exactly what CCleaner plans to remove.

Confirming You Are Cleaning the Right Drive

After you select a drive and click Analyze, CCleaner shows you a list of files it found. At the top of the results window, you should see the drive letter or drive name — for example, "D: Data Drive" or "E: External USB." Confirm this is the drive you meant to target before you click Run Cleaner.

If you see the wrong drive listed, click back to the drive selection screen, pick the correct drive, and run Analyze again. This extra step takes ten seconds and prevents you from accidentally deleting files from the wrong location.

Some versions of CCleaner also show the drive's total size and used space in the results. Use this as a second check — if you know your external drive is 500 GB but CCleaner shows 1 TB, you may have selected the wrong drive.

Why CCleaner Might Not See Your Drive

If a drive you want to clean does not appear in CCleaner's drive list, the most common reason is that it is not plugged in or mounted. Disconnect and reconnect the external drive, wait a few seconds, and restart CCleaner. It should appear in the list.

If the drive is plugged in but still does not show up, check that Windows itself recognizes it. Open File Explorer and look for the drive in the left sidebar under "This PC." If it is not there, Windows has not mounted it, and CCleaner will not see it either. You may need to assign it a drive letter or troubleshoot the connection.

Network drives (mapped network locations) do not appear in CCleaner's drive list. CCleaner can only clean drives that are directly connected to your computer or mounted as local drives. If you need to clean a network location, you will need to do that through the network device's own tools or software.

Frequently Asked Questions

Can I clean multiple drives at once with CCleaner?

CCleaner Free cleans one drive per run. CCleaner Professional can be set to clean multiple drives in sequence if you use the scheduler, but the manual interface still targets one drive at a time. If you want to clean both your C: drive and a D: drive, run the scan twice — once for each drive.

Will CCleaner delete my files if I point it at the wrong drive?

Yes, if you select the wrong drive and click Run Cleaner, it will delete temporary files and cache from that drive. This is why you should always run Analyze first and check which drive is listed in the results before you click Run Cleaner. If you make a mistake, you cannot undo it, so take the extra moment to confirm.

Do I need to eject an external drive after CCleaner cleans it?

No, CCleaner does not lock the drive. You can unplug it when ready after cleaning finishes, or leave it plugged in. If you want to be cautious, use Windows' "Eject" option in File Explorer to safely remove it, but it is not required after a CCleaner run.

Can CCleaner clean a drive that is currently in use by Windows?

Yes. CCleaner can clean your C: drive while Windows is running, because it only removes temporary and cache files that Windows is not actively using. However, if a file is locked by a running program, CCleaner will skip it and move on. Restarting your computer before cleaning can allow CCleaner to remove more files, but it is not necessary.

What if my external drive is formatted as Mac or Linux, not NTFS?

CCleaner works best with NTFS, FAT32, and exFAT drives. If your external drive uses a Mac format (HFS+) or Linux format (ext4), CCleaner may not recognize it or may not be able to clean it properly. Check your drive's format in File Explorer or Disk Management before you try to clean it with CCleaner.