Windows 10 changing .zip file association

7-Zip does not associate itself with the various compressed file types.

To associate .zip file types with 7-Zip, do the following:

1. Open the 7-Zip File Manager with Administrator Rights from your start menu
2. Go to the tools menu and select options
3. Either select the individual extensions you wish to associate or press the “Select All” button (recommended).
4. Press OK to save your changes

Source: https://community.spiceworks.com/how_to/45718-set-file-associations-to-work-with-7-zip-in-windows-7-windows-server-2008-r2

Elevate the 7-Zip File Manager to run as an administrator. Then click menu Tools → Options and choose your file associations.

Or if you're in an elevated command prompt you can use assoc and ftype to tweak your system:

C:\WINDOWS\system32>assoc .zip=7-Zip.zip
.zip=7-Zip.zip

C:\WINDOWS\system32>ftype 7-Zip.zip=C:\Program Files\7-Zip\7zFM.exe
7-Zip.zip=C:\Program Files\7-Zip\7zFM.exe

The default for .zip is CompressedFolder:

C:\WINDOWS\system32>assoc .zip=CompressedFolder

C:\WINDOWS\system32>ftype CompressedFolder=%SystemRoot%\Explorer.exe /idlist,%I,%L