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When viewing a collection, select the the Browse Servlet option from the list of available actions. This will bring you to a separate servlet showing a list of all monitored files and directories for the collection. Selecting a File will then bring up information about the File, including actions to take on that item. Selecting 
Remove will remove the File from tracking in the Collection, and the page will likely need to be refreshed to accurately display the contents of the Collection.
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If a File has been intentionally removed from disk and needs to be removed from ACE AM, a File Audit can be run in order for it to be marked as Missing. Once missing, the 
option a file has been marked as Missing, the Report Servlet can be selected in order to view the Report from the latest Audit. From the Report Servlet, the missing file can be removed by using any of the Remove actions (all, selection, single). The ACE AM will then prompt for confirmation to remove the File(s) after which they will no longer be tracked by ACE AM. A File Audit should be run after removing any files from the Report Servlet so that the error status of the collection can be cleared.
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