When users install utility tools like system cleaners, they expect performance improvements, not data loss. In early 2024, Avast Cleanup Premium, a widely used PC optimization software, unintentionally disrupted many users’ browser environments by mistakenly deleting user profile folders. This unexpected issue left some users without bookmarks, saved passwords, browsing histories, and extensions—vital components of the browsing experience.
TLDR:
In early 2024, Avast Cleanup Premium mistakenly identified browser profile folders as unwanted junk and deleted them. This incident primarily impacted users of Chrome-based and Firefox-based browsers. Fortunately, most affected users were able to recover their profiles using the Avast Profile Restore tool and by adding proper exclusions for browser data. Avast has since adjusted its algorithms to prevent such errors in future versions.
What Happened?
Following an update to its cleanup algorithms, Avast Cleanup Premium began marking certain directories used by popular browsers such as Google Chrome, Mozilla Firefox, Brave, and others as unnecessary “user cache” or “leftover” files. In routine maintenance cleanups, the program erased these directories if users opted for automatic cleanup or selected suggested system junk removal options without realizing the implications.
Because browser profiles are typically stored in subfolders under default AppData or UserData directories—locations that Avast scans by default—the software erroneously targeted and removed files that constituted the entire user browser profile. This meant vital information, including:
- Bookmarks
- Extensions
- Cookies and saved login data
- Browsing history
were completely erased from some users’ systems, making it appear as if they were launching their browsers for the first time.
This deletion not only disrupted workflow and interrupted access to essential tools and saved data but also raised privacy and security concerns for users depending on browser-based login sessions and password storage.
User Reactions and Early Reports
The incident surfaced when users across community forums, Reddit threads, and Avast support channels began reporting that their web browsers had either reset or lost all configuration. Initial confusion suggested a browser update or operating system bug—but patterns soon emerged linking the issue directly to recent cleanups conducted using Avast Cleanup Premium.
One user wrote, “I launched Chrome this morning and everything was gone—my login sessions, my extensions, even my bookmarks from years ago. The only variable was a system cleanup I ran with Avast last night.”
Upon deeper investigation, tech-savvy users and Avast’s support teams realized that the “Browser Data” and “System Junk” cleanup categories were sometimes misclassifying browser profile folders. This misclassification stemmed from a subtle change to Avast’s heuristics designed to better identify data left over from uninstalled software or crash reports—ironically combining browser profile files into that group under certain name/path matches.
Introducing the Profile Restore Feature
In response to the backlash and legitimate user concerns, Avast engineers rapidly developed and rolled out a new module called “Profile Restore.” Built directly into Avast Cleanup’s interface in version 23.3.2 and later, the goal of this feature was to let users bring back mistakenly deleted session data.
How Profile Restore Works:
- When a cleanup is performed, Avast now logs all deleted files with metadata—including exact path, time of deletion, and classification reason.
- If a user accesses the “Recovery Center” module within Avast Cleanup, they can now browse deletions by category—including a newly added “Browser Profiles” section.
- Users can preview which browser profiles were modified or deleted and select to restore them instantly with one click—returning all relevant files to their original locations.
This process gave immediate relief to a significant portion of users who acted quickly enough and hadn’t yet overwritten profile data by reinstalling browsers or generating large amounts of new local files.
Setting Up Exclusions to Avoid Future Issues
To supplement the restore feature, Avast also updated its documentation and provided clearer guidelines for how to exclude specific folders from cleanup routines. Users were advised to create custom exclusions that would prevent browser profile folders from being scanned or altered.
Common File Path Exclusion Examples:
- Chrome:
C:\Users\[YourUserName]\AppData\Local\Google\Chrome\User Data\ - Firefox:
C:\Users\[YourUserName]\AppData\Roaming\Mozilla\Firefox\Profiles\ - Brave:
C:\Users\[YourUserName]\AppData\Local\BraveSoftware\Brave-Browser\User Data\
Avast encouraged users to add these custom paths under “Exclusions” in both Cleanup Premium and any installed antivirus modules to preserve stability and avoid interfering with valid, regularly-used data.
Moreover, Avast introduced automatic exclusions in a hotfix rolled out shortly after the incident. These exclusions detect running instances of web browsers and automatically apply protection to active profiles, reducing dependence on manual configuration.
Lessons Learned and Moving Forward
This incident underscores a looming risk for all system optimization tools: a delicate balance must be struck between improving performance and maintaining data integrity. As automation becomes central to such tools, developers must build resilient safeguards to prevent false positives in file categorization.
Avast’s error stemmed from pattern-based cleanup logic, which, while powerful, lacked the context-awareness necessary to differentiate between redundant application data and essential user content. Profile names, structure, and location can vary significantly, further complicating automated interpretation.
Key Takeaways:
- Users should stay informed: Always review what files are selected before allowing a cleanup tool to proceed—especially if it claims to remove “junk.”
- Backup is critical: Maintaining regular system backups or using browser sync features (like Google Sync or Firefox Sync) adds a crucial layer of safety.
- Developers must remain vigilant: Avast’s quick action to build a restore feature and push auto-exclusion updates deserves credit, but the initial oversight highlights the importance of robust testing against real-world usage patterns.
According to Avast, less than 1.6% of users were affected by the bug, with over 90% of those able to recover their profiles through the Profile Restore tool introduced post-incident. Still, even one percent is significant when software is installed on millions of devices worldwide.
Conclusion
This event serves as a reminder that while cleanup and optimization tools can help streamline PC performance and eliminate clutter, they must be used with care. Avast’s response was comprehensive—acknowledging the mistake, providing useful recovery tools, and improving user protections. Users, on their part, can implement good habits like setting folder exclusions and syncing browser profiles online to avoid local data loss.
Going forward, Avast and similar software vendors are expected to adopt even more intelligent cleanup algorithms and UI/UX designs that prioritize user data safety first. Until then, close attention to what we allow automated tools to handle remains essential.