I had created a Fine Grained Password Policy (FGPP) which, among other things, turned off the requirement for complex passwords. I had applied this policy to users through a group. When I tried to reset the password of one of the users for which this FGPP applied, Active Directory Users and Computers would give me this error:
Active Directory Domain Services
Windows cannot complete the password change for <user> because:
The password does not meet the password policy requirements. Check the minimum password length, password complexity and password history requirements.
Originally I though that my password did in fact violate my FGPP, but after testing this further I concluded that it was something else. After a bit of looking I discovered that this domain was in Windows Server 2003 Functional Mode. A requirement for FGPP is at least Windows Server 2008 Functional Mode. After changing it to Windows Server 2008, the FGPP took effect and I could reset my passwords.
Perhaps the *-ADFineGrainedPasswordPolicy cmdlets should check the domain functional level. At least New-ADFineGrainedPasswordPolicy should display a warning if the domain is not at the required level. The requirement is listed in the Step-by-Step guide (thank you PTS), but I didn’t catch that this time.