In Excel PI Datalink version 5.6.0.0, I need to add a data server, but I get error: Unable to write PISDK registry key Access is denied.AllowLoginPrompt.

I don't seem to have that set of tools installed. I looked through the PI Datalink installation files, and the only thing that seems to be available is the dll files used to implement the excel add-in. Even if I did, I suspect that the registry problem would still block me.

It's a separate application, and would be under the "PI" folder under the Windows start menu. Alternatively, can you run Excel as Admin? That can sometimes fix the problem. Knowledge (osisoft.com)

Right, I used to have and use that, but when my PC was replaced (and updated to Windows 11) I don't have the "PI" installation. Now I'm wondering if maybe there are pieces missing? (Though I thought the excel Add-in was pretty self-contained). I'm currently trying the Excel as Admin, but that's more complicated than it used to be now that we're using Office 365 products..

My IT group was finally able to resolve this. There was a missing pass-through path definition (I'm not quite sure what was missing) into LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\Registry\Machine\Software\Microsoft\AppV\Subsystem\VirtualRegistry

Try opening "About PI-SDK" on your computer, and add it there instead!

These are the 2 entries need to be added to PassThroughPaths. It require admin rights to update the entries and has to be done by System Admin on user machines. more details on KB0026751

• HKEY_LOCAL_MACHINE\SOFTWARE\PISystem
• HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\PISystem

Note - For Datalink 2023, About PI-SDK is not supplied as part of install and it is not possible to clear KST entries manually. this is best workaround that I was able to find.