: A file with the .7z extension is a compressed folder. You need software like 7-Zip or WinRAR to open it.
: In gaming and fan communities (specifically Stargate ), this often names a mod pack or game asset file. SGC.7z
If you can tell me , I can give you a much more specific answer. Is it a file on your computer , a website link , or part of a error message ? : A file with the