How to Reset Permissions on Public Folders
If the Windows user interface has been used to modify client permissions for a public folder through the M:\ drive, Exchange Server 2003 may no longer be able to convert them to MAPI form. To reset permissions on public folders and enable Outlook and Exchange System Manager to edit permissions, perform the following procedure.
Before You Begin
Be aware that after you use this procedure, the affected public folders will have permissions for only the folder owner (an administrative account), Default users, and Anonymous users.
To reset permissions on public folders
In Exchange System Manager, under the Public Folders node, create a new top-level folder.
Move the affected folder and subfolders (those with the wrong permissions settings) into this new folder.
Set the permissions on the new top-level folder so that an account with administrator permissions in Active Directory is the owner.
Right-click the new top-level folder, point to All Tasks, click Propagate Settings, and then select the Administrative Rights and Folder Rights check boxes.
After you click OK, the changes to the permissions are applied to all subfolders of the new top-level folder.
Move the affected folder and subfolders back to their original locations in the Public Folders tree.
Verify that, in Exchange System Manager, you can now modify the permissions.