Perform the following steps to ensure that all users only see one style, without the ability to change to another.
From Cognos Connection
1) Login as an administrator
2) Select Tools -> Portal Administration -> Style tab
3) Check the boxes for all styles you don’t want the user to have access to and press Delete
Another option to is to replace the Cognos Corporate style with the desired style, but retain the name 'Corporate'. Corporate is the default style that all users will see automatically with no changes in login information. This does not prevent users who can access the 'My Preferences' option from changing their 'style'.
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