Following these instructions provided by Netapp support has resolved this issue for me...
1. One either filer head issue the command - cli> cf disable
2. Issue the following command on both heads – cli> halt –s
3. Power down both heads first and then all shelfs
4. Power on one shelf at a time waiting for the shelf to fully initialize before powering on the next shelf
5. After all shelfs are powered on and initialized, power on one of the filer heads. (doesn’t matter which one)
6. After it is powered on and initialized, power on the last filer head and let me know the results.