Avast preventing creation of .mp4 or .raw files

Avast Free Antivirus / Premium Security
1

Hello,

  1. We’re developing a professional software that imports data from an inspection device, connected through SMB to a Windows 11 laptop. During the import process, our software copies several GB’s of data, and at the end it creates an MP4 video from thermal raw data. However, several customers have reported that with their Avast antivirus activated, the MP4 videos were not created successfully, which is a major issue. All other files are created correctly, and other AVI files are copied successfully as well. The video is created with OpenCV, and frames are written one by one in the file. By default, data are imported in “MyDocuments”. An Avast popup also appears, telling the “Ransomware Shield” protected the file, while it actually prevented the file from being created.

  2. We also have another issue where a 3D viewer creates a file to save octrees in a binary format with the extension “.raw”, and Avast is also preventing the files from being written correctly, causing the software to subsequently crash. This is another major issue affecting our business.

In both cases, deactivating Avast works fine immediately, in a fully repeatable way.

What is the cause of Avast preventing a software from creating .mp4 or .raw files? How can we fix that?
Our software executable is signed, the installer is signed.

Thanks.

2

Hi,

Is there a specific pop-up error notification from Avast?
If not, it might be caused by Ransomware Shield. If so, users can add an exception for the application.
How do I allow or block specific applications from modifying files in my protected folders?
https://support.avast.com/article/antivirus-ransomware-shield-faq/#idt_060

3

Yes, a popup appears saying that the Ransomware Shield “protected” the files. But in that case it actually prevented the user from saving his data, resulting in data losses.

Why does this not happen everytime we save something in the MyDocument folder (e.g. MS Word, etc) but only with our software? What is different? What can we do to avoid that?

Thanks for the solution to add the software to the expections; this may help already.
However, our customers need a solution that works out of the box, they are not IT people, we cannot expect them to fine-tune their antivirus each time they want to use a software. And by default, Avast is creating these issues.

Is there anything else we can do to avoid that? (registering, signing, etc.)

Thanks !

4

Hi,

You can submit the latest update for whitelisting as described here: https://support.avast.com/en-ww/article/Threat-Lab-file-whitelist/