In 2017, a signed update for CCleaner—one of the world’s most popular PC cleaning tools—secretly installed a backdoor on over two million Windows machines. The incident exposed a chilling truth: the very software trusted to keep systems clean can become a vector for malware. Seven years later, security researchers and Windows enthusiasts are still warning users to steer clear of so-called “optimizer” suites, from CCleaner to Advanced SystemCare and Clean Master.

A recent MakeUseOf roundup doubled down on that warning, calling out three well-known optimizer apps for making PCs worse rather than better. The broader Windows community has amplified the message, pointing out that Windows 10 and 11 already ship with safe, effective maintenance tools that make third-party tune-up suites not just redundant, but dangerous. This article unpacks the risks behind the three offending apps, explains why built-in Windows tools are the superior choice, and offers a practical maintenance playbook for everyday users.

CCleaner: From Trusted Cleaner to Supply-Chain Nightmare

The 2017 Compromise

CCleaner, now owned by Avast, was long the face of free disk cleanup. But on September 18, 2017, researchers discovered that an official, digitally signed CCleaner installer had been trojanized with a backdoor called ShadowPad. Attackers had compromised Piriform’s build system, pushing malware to users for nearly a month before detection. Wired’s detailed investigation revealed that the attack targeted high-profile technology companies, making it a textbook supply-chain compromise.

The fallout was severe. Because CCleaner runs with elevated privileges—necessary to scrub system files and the registry—the malicious payload had free rein to exfiltrate data, download additional malware, and maintain stealthy access. Users who downloaded CCleaner during that window unwittingly invited attackers into their systems. The incident demonstrated that even trusted, signed software can become a weapon if the distribution pipeline is breached.

The Privacy Betrayal: Avast and Jumpshot

Complicating matters further, Avast’s reputation took a major hit in 2024 when the Federal Trade Commission (FTC) ordered the company to stop selling browsing data collected through its antivirus and subsidiary products. An investigation revealed that Avast’s Jumpshot subsidiary harvested and sold granular browsing records to dozens of third parties—data that CCleaner users likely contributed to. The FTC ruling required Avast to delete that data and imposed strict consent barriers, but for many users, the trust was broken beyond repair.

Persistent Nagging and Bloat

Even without the security and privacy scandals, CCleaner’s user experience has eroded. Windows forums are rife with complaints about intrusive pop-ups pushing paid versions, bundled software, and automated scans that disrupt workflows. One user on WindowsForum described it as “bloatware masquerading as a utility,” noting that the constant upsells made the tool more distracting than helpful.

Advanced SystemCare: The Performance Paradox

All-in-One or All-in-Threat?

Advanced SystemCare from IObit markets itself as an all-in-one tune-up suite: registry cleaner, RAM booster, driver updater, and more. For non-technical users, the long feature list seems comprehensive. In practice, however, many of these features either provide negligible benefit or actively harm performance.

Registry cleaners, for example, are a perennial myth. Microsoft explicitly warns that registry cleaners are unsupported and can cause serious system issues. On modern Windows installations, removing orphaned keys does virtually nothing to speed up a PC. Yet Advanced SystemCare aggressively promotes its registry cleaning as a core value proposition.

The Background Hog

Community reports on IObit’s own forums and Reddit paint a grim picture: the Performance Monitor and other “smart” optimizers often consume significant CPU and RAM themselves. One Reddit thread detailed how the software’s continuous monitoring service kept a laptop’s fan spinning long after boot, while the built-in Task Manager showed the optimizer itself responsible for the constant load. Users have described it as a “placebo that creates the very problem it claims to solve.”

Upsells and Unwanted Extensions

IObit’s business model relies heavily on upselling to premium tiers. Users report persistent installation of browser extensions like Surfing Protection & Ads Removal, which clutter the system and add yet another background process. The combination of intrusive upsells, questionable browser add-ons, and resource-hungry services has led many Windows enthusiasts to recommend uninstallation.

Clean Master for PC: A Legacy of Deception

Cheetah Mobile’s Checkered Past

Clean Master for PC traces its lineage to Cheetah Mobile, a company whose mobile apps were repeatedly flagged for deceptive advertising. In 2018, Google removed several Cheetah Mobile apps from the Play Store after researchers uncovered a scheme that served fake virus warnings in pop-ups to trick users into installing the software. The ads were part of a broader ad-fraud infrastructure that claimed illegitimate attribution for app installs.

This behavior is not a one-off. Beebom and other outlets documented how Clean Master’s mobile version used scare tactics for years. The PC version, while less aggressively documented, carries the same developer fingerprint and business ethics.

Executive Misconduct

In 2022, the U.S. Securities and Exchange Commission (SEC) charged Cheetah Mobile’s CEO and a former president with insider trading. The SEC order detailed trades made while the executives possessed material nonpublic information about the company’s performance. While corporate governance issues don’t directly compromise software security, they are a powerful signal about the reliability of a closed-source utility that asks for deep system access.

Why Closed-Source Cleaners Demand Extreme Trust

A system cleaner requires elevated privileges to delete files, modify registry keys, and stop services. If the vendor engages in misrepresentation or fraud, as the SEC charges suggest, there is little assurance that the software doesn’t have hidden data-collection hooks or exploitable flaws. For a tool that advertises itself as a security and performance aid, Clean Master’s baggage makes it an unacceptable risk.

Windows Already Has Built-in Maintenance Tools—and They’re Safer

Storage Sense and Cleanup Recommendations

Windows 10 and 11 include Storage Sense, which can automatically delete temporary files, empty the Recycle Bin, and remove old Windows Update leftovers. You can configure it to run on a schedule or on-demand. The newer Cleanup Recommendations feature goes further, suggesting large or unused files for removal. These integrated tools do exactly what disk cleaners do, but without third-party risk.

Task Manager Startup Control

One of the biggest real-world performance improvements comes from pruning startup items. Third-party optimizers often include a startup manager, but Task Manager already provides a detailed view of which programs launch at boot and their resource impact. No extra installation needed.

System File Repair with SFC and DISM

When performance problems stem from corrupted system files, the built-in System File Checker (SFC) and Deployment Image Servicing and Management (DISM) can repair them—without guesswork or registry surgery. Advanced SystemCare’s registry cleaner cannot match the precision of Microsoft’s own integrity tools.

PC Health Check and Microsoft PC Manager

For users who want a dashboard-style overview, Microsoft offers the PC Health Check app (for Windows 11 compatibility and basic diagnostics) and the more recent Microsoft PC Manager. These free tools provide storage insights, startup time estimates, and battery health—exactly the “one-click” overview that optimizer vendors sell, but without the bloat or privacy invasions.

The Practical Maintenance Playbook

For the vast majority of Windows users, the following free, built-in steps cover all routine maintenance:

  • Enable Storage Sense via Settings → System → Storage. Configure it to run weekly and clean temporary files automatically.
  • Audit startup apps in Task Manager (Ctrl+Shift+Esc → Startup tab). Disable any program you don’t need immediately at sign-in.
  • Run Disk Cleanup as Administrator for a manual sweep of system files, including old Windows updates and delivery optimization files.
  • Use SFC and DISM only when you suspect system corruption: open Command Prompt as admin and run DISM /Online /Cleanup-Image /RestoreHealth followed by sfc /scannow.
  • Uninstall problematic apps with Windows’ own Apps & Features, or for stubborn leftovers, use a focused tool like Bulk Crap Uninstaller (BCUninstaller)—never an all-in-one optimizer that might do more damage than good.

Recovery Checklist: When an Optimizer Has Already Done Damage

If you previously installed an optimizer and now experience crashes, slowdowns, or strange pop-ups, follow these steps:

  1. Uninstall the optimizer via Settings → Apps. Follow up with BCUninstaller to remove lingering files and registry entries.
  2. Run a full antivirus scan with Windows Security (Offline scan recommended) and a second-opinion scanner like Malwarebytes.
  3. Repair system files with the DISM/SFC combo as described above.
  4. Check Task Manager and Autoruns for persistent services or scheduled tasks left behind. Sysinternals Autoruns can reveal deeply hidden autostart entries.
  5. Reset your browsers if you find unexpected search engines, toolbars, or extensions. Reinstall only trusted extensions from official stores.
  6. Consider a clean install if you suspect backdoor access or ongoing compromise. Back up your data and reinstall Windows from official Microsoft media.

When Third-Party Tools Still Make Sense—and How to Pick Them

Not every third-party utility is toxic. Power users often rely on specialized tools that Windows doesn’t natively provide:

  • Bulk Crap Uninstaller for mass application removal and leftover cleanup.
  • Autoruns from Sysinternals for forensic autostart auditing.
  • Process Explorer or MiTeC Task Manager DeLuxe for advanced process diagnostics.

If you choose a third-party tool, vet the vendor carefully. Look for:

  • Transparent privacy policies that explicitly state data handling.
  • A clean incident history with no supply-chain compromises or FTC sanctions.
  • Open-source or independently auditable code where possible.
  • No persistent background agents or bundled browser extensions.

Avoid any tool that promises extraordinary gains (“boot time reduced by 50%”) or that installs a suite of always-on services. The WindowsForum discussion thread emphasized that even well-meaning utilities can degrade performance if they run continuous monitoring.

The Bottom Line: Safer, Cleaner, and Backed by Microsoft

The MakeUseOf article and the ensuing WindowsForum discussion converge on a simple truth: modern Windows is self-sufficient for routine maintenance. The three optimizer apps highlighted—CCleaner, Advanced SystemCare, and Clean Master—carry documented, severe risks ranging from supply-chain attacks to deceptive business practices and performance-harming background services.

Leaning on Storage Sense, Task Manager, SFC, and PC Health Check doesn’t just reduce your attack surface; it eliminates the entire category of problems that third-party optimizers introduce. As one forum member put it, “The extra five minutes of manual cleanup a month is a small price to pay to avoid a weekend of reinstalling Windows after a ‘cleaner’ wrecks your system.”

For the security-conscious Windows user, the message is clear: stop paying for or downloading tools that promise to fix what isn’t broken. The free, built-in maintenance features already on your PC are not only adequate—they’re safer. And in an era where even signed updates can harbor malware, sticking with Microsoft’s own code is the most prudent maintenance strategy of all.