Unable to register 7zip to open zip files  

Callender, before posting I did everything as you mention, although the menu settings of the latest version (18.05, 2018-04-30 ) are a bit different. It made no difference, so it's still missing from the context menu.

Have you actually installed the 32bit version of 7zip on a 64bit machine by any chance? If so uninstall it and install the correct version.

https://www.7-zip.org/download.html

It is the 64 bit version :-(

Okay - I reckon that you might need to uninstall 7-Zip using this:

Geek Uninstaller - the best FREE uninstaller

Allow it to scan for leftovers and delete anything found. If any of these registry entries exists - delete:

Computer\HKEY_CLASSES_ROOT\*\shellex\ContextMenuHandlers\7-Zip

Computer\HKEY_CLASSES_ROOT\Directory\shellex\ContextMenuHandlers\7-Zip

Computer\HKEY_CLASSES_ROOT\Folder\shellex\ContextMenuHandlers\7-Zip

Reboot then try installing Z-Zip again.

Callender said:

Okay - I reckon that you might need to uninstall 7-Zip using this:
Geek Uninstaller - the best FREE uninstaller
Allow it to scan for leftovers and delete anything found. If any of these registry entries exists - delete:
Computer\HKEY_CLASSES_ROOT\*\shellex\ContextMenuHandlers\7-Zip
Computer\HKEY_CLASSES_ROOT\Directory\shellex\ContextMenuHandlers\7-Zip
Computer\HKEY_CLASSES_ROOT\Folder\shellex\ContextMenuHandlers\7-Zip
Reboot then try installing Z-Zip again.

Thanks for the Geek Installer link. Did all the above listed. There were no entries left in the Registry, rebooted and reinstalled it, but 7Zip is not listed in the context menu.

I am facing two other minor issues with the Explorer which may have a bearing on this. One is that 'Quick access' never worked, it won't retain anything added to it, and the Explorer Desktop link is mixed up with the Downloads folder link.

FYI:

Reset File Explorer Quick Access Toolbar to Default in Windows 10 | Windows 10 Tutorials

Or just remove it if you don't use it:

Remove Quick access from Navigation Pane in Windows 10 | Windows 10 Tutorials

Try this:

Restore Default Location of Personal Folders in Windows 10 | Windows 10 Tutorials

You could be right - something may have screwed up explorer.

Another idea, although it doesn't fix 7-zip context menu. If you just need 7-zip to extract files from Windows ISO's - use the portable version. For other tasks try Peazip (installed). It does just about everything else. Plus you could see if it actually shows up in context menu.

ineuw said:

Did all the above listed. There were no entries left in the Registry, rebooted and reinstalled it, but 7Zip is not listed in the context menu.

You did try re-adding it to context menu after the reboot/ reinstall as per this post? It doesn't show up otherwise.

Unable to register 7zip to open zip files - Windows 10 Forums

OP can register to open zip files. There is a problem with the right click context menu not showing. 7-Zip does open zip files when they are double clicked. FYI: For me there is no problem but I'm on 1803.