Some users Windows 10 users have reported a strange bug where when they right-click on a file, the “Open with …” option is missing.
This option is very important as it allows users to choose one application to open that file. Especially for unknown files or files that have not been associated with a default program this option is sometimes the fastest way to set a default program.
If the option is missing from your system then it is usually your registry fault Windows. It's easy enough to get it back. See below what you need to do.
1. Open the execution window by pressing the Win + R keys at the same time
2. Enter the word regedit there and press the OK button
3. If User Account Control (UAC) asks for your confirmation to allow Registry Editor to make changes to your system, say Yes
4. In the new window with the Registry Editor to open, navigate to the following location.
HKEY_CLASSES_ROOT \ * \ shellex \ ContextMenuHandlers
The asterisk is a real one key registry and is not something that should be replaced with a specific user key value.
5. Right-click in the right pane and create a new key here through Create> Key and name it "Open With". Chances are the key already exists and if so then just go to the next step.
6. Then right-click on the new or existing “Open With” key and click Modify. In the new window, edit the "Value data" field to indicate the following: {09799AFB-AD67-11d1-ABCD-00C04FC30936}
7. Click "OK", close the registry editor (do not worry about saving, the data is saved automatically).
You should now have the “Open with” option back in the right-click menu. If you don't see it right away, try againmovement of explorer.exe or if you don't know how to restart the whole computer.
If for some reason the option does not return to the right-click menu, you may be blamed for something other than the Windows registry. If this is the case, do all of the Update proposed by Microsoft, since the problem is already known to it and the probability will be solved immediately with subsequent upgrades.