So I have been trying to get AD LDS to work, I had an earlier question the solution of which is to extend the schema which I solved.
So I tried to create a new computer object and I got the error.
Operation failed. Error code: An invalid directory pathname was passed
So another SO question has this error but for a user script. This is Microsoft's GUI applet.
EDIT: I restarted the service and deleted other experimental AD LDS instances and then restart ADSI Edit and it worked.
I restarted the service and deleted other experimental AD LDS instances and then restart ADSI Edit and it worked. Solved.