Some customization about Windows10.

   After installing Windows10, SearchUI.exe accesses the Internet frequently. I find it annoying and don’t need it. I found SearchUI.exe in the folder %windir%SystemAppsMicrosoft.Windows.Cortana_cw5n1h2txyewy. For killing SearchUI.exe, I wanted to change the folder name. So I did the following steps.

1. Hit [Windows] key + [R] key.
2. Type ‘msconfig’ and click [OK].
3. Select ‘Boot’ tag and check ‘Safe boot’. Click [OK].
4. Reboot the PC.
5. About SearchUI.exe on Windows10 1511, Safe boot doesn’t work well anymore.
   Run cmd.exe as Administrator.
   > taskkill /F /IM SearchUI.exe
   Go to %windir%SystemApps and change the folder name, something like Microsoft.Windows.Cortana_cw5n1h2txyewy.bak.
   [Caution]: After doing the command above, rename the Cortana App folder immediately. You must have speed because SearchUI.exe respawns very quickly.
   [Caution2]: On 2016.Aug.10 I updated to Redstone1, and I couldn’t change the Cortana folder name manually. SearchUI.exe respawns very very very quickly. You’d better use a batch file like this.
6. Hit [Windows] key + [R] key.
7. Type ‘msconfig’ and click [OK].
8. Select ‘Boot’ tag and uncheck ‘Safe boot’. Click [OK].
9. Reboot the PC.
   At the time, SearchUI.exe doesn’t run anymore.
10. Next, edit registry.
    Run regedit.exe.
11. Add the next key.
    [HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoftWindowsWindows Search]
"AllowCortana"=dword:00000000
12. Now you cannot use ‘Search Box’ on the task bar but it is still visible.
    So, right click on the task bar.
    Select the ‘Cortana’ option.
    Select ‘Hidden’.

   I think the steps above kill all Cortana features.

   I don’t use ‘OneDrive’. I changed its options, but it still remains the left pane of Explorer, annoying.

1. Run a cmd.exe as Administrator.
2. start /wait "" "C:WindowsSystem32OneDriveSetup.exe" /UNINSTALL
   
   If you have 64-bit Windows10,
   start /wait "" "C:WindowsSysWOW64OneDriveSetup.exe" /UNINSTALL
3. Go to C: and delete the folder OneDriveTemp, if it exists.
4. Go to %USERPROFILE% and delete the folder OneDrive.
5. Go to %LOCALAPPDATA%Microsoft and delete the folder OneDrive.
6. Go to %PROGRAMDATA% and delete the folder Microsoft OneDrive.
7. Next, edit registry.
   Run regedit.exe.
8. Select the key HKEY_CLASSES_ROOTCLSID{018D5C66-4533-4307-9B53-224DE2ED1FE6}ShellFolder, and change Attributes data, default is f080004d.
   "Attributes"=dword:00000000
9. Add the followings.
   [HKEY_CLASSES_ROOTWow6432nodeCLSID{018D5C66-4533-4307-9B53
-224DE2ED1FE6}ShellFolder]
"Attributes"=dword:00000000
10. Reboot the PC.
    OneDrive has gone from the left pane of Explorer.

   Ref URL: Remove Bloat from Windows 10

Edit3(2017.Jun.13):
   Today, I’ve found Cortana back after Windows Update. Besides, Start Menu is disabled if I kill Cortana, and Colrtana is back if I fix Start Menu malfunction. Umm. I give up against fighting for Cortana at this point.