The 8770 error occurs when the server attempts to remove an internal unique file ID from a list as a file is closed, but that file ID is not on the list. This might be caused by an application opening different files with the same internal file ID. This would typically be the case when a file is copied and both files are then opened; therefore they both have the same file ID. To avoid these errors do not copy server-controlled files. If the 8770 error occurred after another more serious error, the 8770 error can be safely ignored. If it recurs, contact your application developer for assistance.