If User1 opens a document and User2 is opening the same document at another client machine, a dialog box pops up with a message “the document is locked by User1”. Ideally If User1 opens the document in readonly mode, User2 should also be able to open the same document in readonly mode simultaneously. So My problem is, how to open a same document with multiple clients simultaneously in readonly mode.
Subject: How to open a same document with multiple clients simultaneously in readonly mode.
There is nothing special about what you describe.
It would seem User 1 is opening in edit mode instead of read. That is either an access control or user eductation issue.
Subject: How to open a same document with multiple clients simultaneously in readonly mode.
Are you using document locking (new R6 feature) ? If so, change the script/formula to only create a lock when the user edits the document.Or disable document locking altogether 
cheers,
tom
Subject: This is no standard behavior
Hi Shuvadip,While this is normal for files (e.g. word). Domino doesn’t expose such behavior. You might want to check: Settings for document locking (that shouldn’t affect readmode) and your query-open/post-open events. There might be some code, that does that.
Hth
stw