I have added some users in Dl list. But these DL list are not showing in the Users member of tab.What could be the issue .

How long after you added them did you wait before you checked the memebership? They may have been added from a different DC than you're using to check them, and there is some replication latency. Or you may need to do a refresh on whatever it is your using to display them. Not enough information to give a good answer.[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "

I have added some users in Dl list. But these DL list are not showing in the Users member of tab.What could be the issue . I assume you are checking in Outlook running in Cached mode. If this is the case, the issue might be caused by OAB downloading error. So firstly please try in OWA or Outlook running in Online mode. If the issue continues, that means the member was not added successfully. Please refer to: Managing Distribution Groups http://technet.microsoft.com/en-us/library/bb125256(EXCHG.80).aspx if the issue disappears in OWA, it could be an OAB downloading issue. Please try the steps I suggested in here: http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/e85e6d92-b5fd-4cfa-ab40-f6d4ec484acd. Hope it is helpful. Fiona