When multi-TIFF images are being imported, Interpret checks whether the file name of each multi-TIFF image file already exists in the ident or unident directory. If the file already exists there, it means that the file has already been imported, and Interpret will not import it again.
This means that if Interpret stops or crashes while multi-TIFF images are being imported, it is safe to move multi-TIFF images from the temp directory back to the source directory and start again, because no duplicate forms are imported.