B1qwer.7z -

or what it's supposed to contain? Knowing the source would help in determining if it's safe to open.

is not a known software product or public service; rather, it is a specific compressed archive file that someone has likely shared with you or that you found online. Because ".7z" is a container format, its safety and value depend entirely on what is inside it. File Overview B1qwer.7z

Use a service like VirusTotal to check the file against dozens of antivirus engines. or what it's supposed to contain