Contrary to this Apple KB article, Windows 7 can be connected to a PDC Domain running on Mac OS X Server. We have successfully connected Windows 7 machines to both a PDC and an Open Directory Master running on Mac OS X Server 10.6 Snow Leopard using the solution below (originally found at MacWindows.)
SUMMARY: tell Windows 7 to NOT encrypt communications to and from the server.
From Windows 7:
- Type Secpol.msc in start button.
- Expand "Local Policies" and select "Security Options."
- Alternate : Type secpol.msc to get editor up then
- Locate "Network Security: LAN Manager Authentication Level" in the list and double-click it.
- Change the setting from "Send NTMLv2 response only" to "Send LM & NTLM -use NTLMv2 session if negotiated" Apply & OK.
- Then locate "Network Security: Minimum session security for NTLM SSP Based (including secure RPC) Clients."
- Change the setting from "require 128 bit" to unchecked (No Minimum).
- Click Apply and OK.