How to reset administrator@vsphere.local password in vCenter 5.5

1. Open command prompt as administrator on the SSO 5.5 server
2. cd /d “C:\Program Files\VMware\Infrastructure\VMware\CIS\vmdird”
3. vdcadmintool.exe
4. Press 3 to enter the username
5. Type: cn=Administrator,cn=users,dc=vSphere,dc=local
6. Hit enter
7. New password is displayed on screen
8. Press 0 to exit

Pretty easy eh?

You can get to the same utility on the VCSA by logging in with root at the console and launching the following command: 

/usr/lib/vmware-vmdir/bin/vdcadmintool

Follow the same process listed above to generate a new password.