Microsoft Defender SmartScreen
BleachBit users may sometimes see an error with a blue box with a message like this:
Windows protected your PC
Microsoft Defender SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.
App: (filename)
Publisher: Open Source Developer, Andrew Ziem
What is Microsoft Defender SmartScreen?
SmartScreen is a security feature in Microsoft Windows that helps protect users from potentially harmful applications and websites by warning them when they attempt to run unrecognized or unsafe software.
How does SmartScreen work?
SmartScreen uses a reputation-based system that estimates the safety of files and applications based on their history and the trustworthiness of their code signing certificates. When a file is downloaded or executed, SmartScreen checks it against a database of known safe and unsafe applications. Newly signed or renewed certificates start with no reputation, leading to warnings until they build a history of trust.
SmartScreen has been criticized for its effect on smaller publishers and its catch-22 effect.
Why does SmartScreen warn about BleachBit?
Users are more likely to see the SmartScreen error in the first days after the release. When BleachBit version 4.6.2 was released on October 7, 2024, it was the first stable release published with a new code signing certificate, so the certificate had little reputation with SmartScreen. Also, this version was new, so it also did not have much reputation with SmartScreen.
How to verify the software
To protect your computer, always download BleachBit only from this official website www.bleachbit.org, and check that it was signed with the name Open Source Developer, Andrew Ziem, as shown in this screenshot. These steps already give you a high degree of confidence.
For an additional check, upload the BleachBit software to VirusTotal for scanning. However, antivirus software sometimes makes a mistake when it detects malware that is not there. Resolving this false positives the BleachBit developers to contact the vendors to correct the error in their scanners, and some vendors are slow to respond.
How to run despite SmartScreen warning?
Once you are satisfied, the next steps are to click on "more info" and the "run anyway" button.
If there is no option to run anyway, here is a way to bring it back:
- Open the Windows Settings.
- Navigate to App & Browser Control.
- Change the options from "Block" to "Warn."
- Run BleachBit again.
Alternatively:
- Right-click on the installer (BleachBit-4.x.x-setup.exe).
- Select the Properties option.
- Check the "Unblock" checkbox at the bottom of the Properties window.
Downgrade
Another option you have is to downgrade to an older release such as BleachBit 4.6.0 that has more reputation with SmartScreen.
If you have additional issues or concerns, see the help page for technical support.