Just to save anyone else the pain - if you are still using the single sign on service and can't get it to work after upgrading to Windows 10 from a previous Windows version, the solution (without having to reinstall the Notes client which does work but not good when you have customers with multiple machines already upgraded to Windows 10) is....

 

1. As mentioned on other forums/postings, you need to ensure that the following registry entry contains "npnotes" for 32-bit Windows and "npnotes64" for 64-bit:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order
Name: "ProviderOrder"

So value must contain npnotes or npnotes64 eg: RDPNP,LanmanWorkstation,webclient,npnotes64

AND it MUST be directly after "webclient" or it will also fail.

 

2. As NOT mentioned anywhere else it would seem is the fact that an entire registry key is missing.  If you copy the following to Notepad and save as .reg you can execute to auto-add the entries:

------------------------------------------------------------------------------------------------------------------------------------
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\npnotes64]
"Group"="NetworkProvider"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\npnotes64\NetworkProvider]
"Name"="IBM Notes Single Logon"
"ProviderPath"="c:\\notes\\npnotes64.dll"
"Class"=dword:00000002
------------------------------------------------------------------------------------------------------------------------------------

 

You will need to change the ProviderPath value to the path of the Notes executables and remove all 3 "64" instances for 32-bit machines (so npnotes/npnotes/npnotes.dll). Obviously check that you actually have the necessary .dll in there!

Also make sure that the IBM Notes Single Logon service is running and set to Auto.

Note a restart IS required!

Please shout if this helped! Thanks.