If what you need is to disable Cortana but keep the Search behavior (as in LTSB/C) this can be accomplished in two ways, through Group Policy or directly editing the registry, this step is explained in many places so I won't insist on it, see here for eg. other tweaks can be made on this matter(disable web connects and such), just look around.
What you will get is the default local Search behavior and this is enough in most cases, however Cortana name&icon will still be seen in both Start Menu and if you're like me this is annoying, I mean why do I still see Cortana circle and name after disabling it, instead of the Search lens icon and name even after disabling and trying every possible tweak...?
With a little reversing, these are the results:
- Cortana or Search is actually SearchUI.exe behaving as one or the other as configured in Group Policy or registry or see next...
- The cosmetics (icon&name) are, strangely, not configured based on this, but checking directly the Cortana-AllowCortana-Enabled value in Product Policy and this actually takes precedence on all these tweaks (for eg. "normal" Windows this flag is set to 1, while on LTSB is 0), 1 is Cortana behaviour(if not disabled in GP/registry), name and icon, when 0 you get the Search ones
- The Product Policy is specific to the Windows edition installed (stored in HKLM\SYSTEM\CurrentControlSet\Control\ProductOptions\ProductPolicy) and Cortana-AllowCortana-Enabled flag is 1 on every regular edition I checked (Home/Pro/Ent) and 0 on LTSB/C ones
Obviously, changing that to zero will get us the desired result, but this is not easily possible since that value is, as expected, a kernel protected registry entry (basically, if modified, one could give Enterprise capabilities to a Home edition), meaning any change you made on a normal session is silently discarded and it's only possible to modify it with some additional steps, see here for the steps, but once modified, the SPP service will kick in at some point in the future and refresh everything back, disabling SPP is also not really recommended since that could also break other things (activation and such).
The other way is what I used, a simple patch to the two dlls (Cortana.BackgroundTask.dll & Cortana.Core.dll) who are checking for that policy flag, once patched to always return false on the Cortana enabled check I got my Search back, exactly as in LTSB (icon/name/behaviour)...
1Removing Cortana in its entirety is going to break Windows Search on Windows 10, that is a side effect, of disabling what now is a core component of Windows. You won’t be able to avoid that issue. If you truly want Cortana disabled, use Windows 10 Enterprise LTSB. – Ramhound – 2018-07-13T12:02:07.993
1@Ramhound Maybe there's a way to hide the Icon instead? – Lyux – 2018-07-13T18:34:52.800
1Have you tried right clicking on the taskbar? You can hide the search/Cortana icon in the context menu, but the search still works when you type in the Start menu. – juniorRubyist – 2019-01-04T21:17:18.197