: Use 7z t 3gj8.7z to verify that the archive isn't corrupted before processing it in your workflow.
: If you just need to open it, 7-Zip for Windows or The Unarchiver for Mac are the most reliable tools. 3gj8.7z
If you are unsure what this file is, you can check its origin or contents: : Use 7z t 3gj8