Blu.7z

Since Windows and macOS don't always support 7z files natively for extraction, you’ll need a third-party utility:

Some users report .blu or blu.7z files appearing in relation to BlueStacks, a popular Android emulator. blu.7z

Have you stumbled across a file named on your hard drive or in a download folder? Unlike standard .zip files, seeing a .7z extension can be a bit confusing if you don't have the right tools. Here is a quick guide on what this file likely is and how you can peek inside. What is a .7z File? Since Windows and macOS don't always support 7z