Be cautious if you find a tmp.7z file in your AppData\Local\Temp folder that you didn't create. Some automated malware reports show that malicious installers or scripts may drop files into temporary directories using names like 7z-out or tmp to execute hidden payloads. If you suspect a file is suspicious, you can scan it with Malwarebytes or VirusTotal .
7-Zip creates temporary files in the target directory (where the final archive will live), not necessarily your current working directory. tmp.7z
Are you trying to a backup with this file, or are you getting an error message when trying to open it? Fresh Windows install triggers Windows Defender, breaks Be cautious if you find a tmp