Last week I upgraded my web server to Windows Server 2008 and of course POP3 Service is missing. The good-old (Microsoft) POP3 service was using Encrypted Password File scheme for authentication. Good news (everyone), I have created a home-custom-made POP3 Server in which I have replicated most features of the original POP3 service and works at least with Outlook and Thunderbird. The only "issue" is that I'd like to replicate also the user passwords instead of just resetting them at the new server. From RFCs and the documentation on technet about POP3 service I saw that there is an MD5 (+CRAM) authentication scheme but the hidden lock file contents on each mailbox do not confront with standard MD5 hash. From the WINPOP command line utility I see that one can migrate this authentication scheme including passwords to Active Directory. I can only presume that the hashing technique is not MD5 but something else or at least not -just- MD5. Question is: how do I decrypt the lock files of POP3 service ?

Yes, I would suggest a Third Party POP3 connector for Windows 2008, better yet Exchange Server, but this is really not an Exchange issue but more a Windows 2008 question. I would try posting to that Group.MVP Exchange Server