Been getting that irritating error (which shouldn’t exist in the first place if you ask me)? Here’s the quick fix:
Right click on the file you want. (No, we’re not going through the old way of 7-zip > Open archive technique.)
Choose ‘Open with…’
Select ‘Choose default program…’
Look for 7-Zip File Manager. If it’s not in the lists of recommended programs, search for it (click ‘Browse…’. Typically it’s under your C:\Program Files\7-Zip folder. Choose the 7zFM.exe program as default program.
Notice that 7-zip GUI is different from 7-zip File Manager. (Aha!)
Click ‘OK’ and try double-clicking your compressed files.
You’re welcome. 
I must have tried that 10 times but the time I try it after reading this, it works. Of course.
Thanks.
Repair corrupted zip file owing to http://www.zip.fixtoolbox.com program supports restoring zip archives of more than 2GB.
Thank you for the fix. Also thanks for the Aha!, reminded me of Alan Partridge, which is always a good thing.
Thanks for such an effective solution.
I’m with you on the “never should have existed in the first place” bit.
Thanks!!
Wow worked for me it was driving me loco…
Thanks for the clear explanation. Why the 7-Zip GUI doesn’t open files directly is beyond me. This problem must happen for every person who Installs 7-Zip for the first time.
Cheers dude. I must have originally selected the wrong default application within 7-Zip, to open archives. Thank you for helping me straighten out Windows 8, I swear I’m going Mac next