>>>>>Yes, if your SQL Server is one of the listed. But this is still not recommended.
>>>>
>>>>Ok where are you seeing that its not recommended ?
>>>>
>>>>I haven't been able to find a reference to best practise about this.
>>>
>>>I believe I read this in many threads in Transact SQL forum at MSDN and could have read in other links as well.
>>
>>So its hearsay ?
>
>We never disconnect users before rebuilding indexes. We run SQL Server Standard edition. Doing a rebuild causes the equivalent of a file lock (if I remember right), however, so long as the rebuild occurs quickly this hasn't been an issue for us. We only rebuild when fragmentation > 20%, otherwise we do a reorganize which doesn't require a file lock.

Thanks Brandon

I'm working at a site where they had poor response times this morning so I suggested a re index. My gut feeling was that people needed to be aware it was happening but if some where connected it wouldn't cause a problem, but one person was saying everyone had to be out of the system or it wouldn't "work".