CCleaner - System Cleaning and Optimization Utility
ccleaner.exe and ccleaner64.exe are generally safe. They are legitimate system cleaning utilities from Piriform (now owned by Avast) that remove temporary files and clean the Windows registry, but users should be aware of the 2017 malware incident and only download from the official website.
ccleaner64.exe (64-bit) and ccleaner.exe (32-bit) are the executable files for CCleaner, a popular system optimization and cleaning utility developed by Piriform, which was acquired by Avast in 2017. CCleaner is designed to remove temporary files, clean browser caches, fix registry issues, and optimize Windows performance by freeing up disk space.
The application has been one of the most downloaded system utilities globally, with over 2 billion downloads. CCleaner can clean temporary internet files, cookies, download history, recent documents lists, and other clutter that accumulates during regular computer use. It also includes a registry cleaner that scans for and removes invalid registry entries, though the usefulness of registry cleaning is debated among experts.
Quick Fact: CCleaner's name comes from "Crap Cleaner" - it was originally designed to remove unwanted files and "crap" from computers. The software has been around since 2004 and remains popular despite security controversies.
Generally yes, but with important caveats. The legitimate ccleaner.exe is safe when downloaded directly from the official Piriform/Avast website. However, CCleaner's reputation was significantly damaged by a 2017 security incident.
The real ccleaner.exe from Piriform/Avast is NOT a virus, but there was a major security breach in 2017 where the official CCleaner download was compromised with malware. Between August and September 2017, hackers inserted a backdoor into the legitimate CCleaner installer (version 5.33), which was downloaded by approximately 2.27 million users. This supply chain attack made CCleaner one of the most significant security incidents in recent software history.
In September 2017, security researchers discovered that CCleaner's official download had been compromised:
C:\Program Files\CCleaner\CCleaner64.exe or C:\Program Files (x86)\CCleaner\CCleaner.exe. Any ccleaner.exe found elsewhere is suspicious.Red Flags for Malware:
CCleaner may be running on your system for several reasons, depending on how you've configured it or how it was installed.
Common reasons CCleaner is running:
Tip: If CCleaner is running at startup and you don't want it to, open CCleaner → Options → Settings → and uncheck "Run CCleaner when the computer starts" and "Enable system monitoring."
Yes, you can safely disable or completely remove CCleaner. CCleaner is a third-party utility program, not a critical Windows system component. Disabling or uninstalling it will not harm your computer or affect Windows functionality.
services.msc, and press Enterappwiz.cpl, and press EnterSafe to Remove: CCleaner is completely optional. Windows has built-in tools (Disk Cleanup, Storage Sense) that can perform similar cleaning tasks without installing third-party software.
While CCleaner typically uses minimal resources (1-5% CPU, 50-150 MB RAM), some users report high resource usage. Here are common causes and solutions:
Quick Fixes for High Resource Usage:
1. Close CCleaner when not actively using it (don't leave it running in background)
2. Disable monitoring and auto-start features in Options → Settings
3. Check if you have version 5.33 (compromised) - if so, uninstall immediately
4. Scan with antivirus to rule out malware impersonating CCleaner
5. Consider using Windows' built-in Disk Cleanup instead
CCleaner can cause temporary 100% disk usage when:
Solution: This is normal behavior during cleaning operations. If disk usage remains high after cleaning completes, close CCleaner or uninstall it.
Normal memory usage: 50-150 MB. If significantly higher:
The legitimate ccleaner.exe from Piriform/Avast is NOT a virus. However, in 2017, the official CCleaner download was compromised with malware (version 5.33), affecting 2.27 million users. To verify legitimacy: check that the file is located in C:\Program Files\CCleaner\, has a valid digital signature from Piriform or Avast, and is not version 5.33. Always download from the official ccleaner.com website.
High CPU or disk usage is normal when CCleaner is actively analyzing or cleaning files. This process typically takes 1-5 minutes. If usage remains high constantly, disable system monitoring in CCleaner settings (Options → Settings → uncheck "Enable system monitoring"), or close CCleaner when not in use. Persistent high usage could indicate an outdated version, corrupted installation, or malware - run an antivirus scan and verify the file's digital signature.
Yes, you can safely delete (uninstall) CCleaner. It's a third-party utility, not a Windows system file, so removing it won't harm your computer. Use Settings → Apps or Control Panel → Programs and Features to uninstall properly. Windows has built-in alternatives like Disk Cleanup and Storage Sense that can perform similar cleaning tasks without third-party software.
Yes. To stop CCleaner from running at startup: 1) Open CCleaner → Options → Settings → uncheck "Run CCleaner when the computer starts" and "Enable system monitoring", or 2) Open Task Manager (Ctrl+Shift+Esc) → Startup tab → right-click CCleaner → Disable. CCleaner will only run when you manually open it.
CCleaner runs at startup if: 1) You enabled "Run CCleaner when the computer starts" in settings, 2) System monitoring is enabled (Professional version feature), 3) Scheduled tasks were created for automatic cleaning, or 4) It was bundled with other software and automatically configured to start. You can disable this in CCleaner's Options → Settings menu or via Windows Task Manager's Startup tab.
In 2017, hackers compromised CCleaner's build system and inserted a backdoor into version 5.33. This malicious version was available for download from the official website from August 15 to September 12, 2017, and was downloaded by approximately 2.27 million users. The malware collected system information and could download additional payloads. Piriform/Avast released a clean version (5.34) once discovered. If you have version 5.33, uninstall immediately and scan for malware.
CCleaner is generally safe if downloaded from the official website (ccleaner.com) and kept updated. The 2017 malware incident was resolved, and security has been improved since Avast's acquisition. However, many experts now question whether CCleaner is necessary, as Windows includes built-in cleaning tools (Disk Cleanup, Storage Sense) that are safer and don't require third-party software. Registry cleaning, one of CCleaner's features, is generally not recommended by Microsoft.
ccleaner.exe is the 32-bit version of CCleaner, while ccleaner64.exe is the 64-bit version. Modern Windows installations (64-bit) will use ccleaner64.exe, which can access more memory and may perform better on 64-bit systems. Both versions have the same functionality; the installer automatically selects the appropriate version for your system. If you see both on your system, the 64-bit version is the one being used.