From which user, you are trying to tresspass the LUN ?

Try using Admin user....

Hi   - my account on Unisphere has full admin rights

The said error refers to "Cannot read the array's Nice Name because the PSM file containing it is not using the current PSM format" It is normally caused  if the driver K10cloneadmin becomes abnormal in the stack leaving the LUN unavailable for trespass. The LUN acts like it is still synchronized.

Steps you can try:

- Restart Mangement Server for the both the SP's.

If that works out good no worries. If that doesn't Refer to KB Article: emc31382 it has step by step instructions.

Is that LUN being used for Clones? Is it the source LUN or the destination LUN? What flare version is running on the CX4

glen

As Ankit mentioned, the Source or destination of a Clone when syncing should not be trespassed.

Also, see the below for best pratices regarding Pool LUNs and SP ownership rules:

emc311319 "Setting the Pool LUN default and allocation ownership correctly"

glen