I am using InDesign CS6 v8.0.1 and I have created a document I am essentially using as a template by using data merge and also using 'Relink to folder' to update images that I have given common names. In most cases the 'Relink to folder' function works, but in a handful of cases I get an 'Import failed' message with no other information. I have been unable to determine the difference in either the documents or the images in the folder.
Wrong file extension, perhaps?
Actually, in looking at that again - I had looked before - I realized it was hanging on a 0 byte file. Removed that one - damaged I guess - and it worked.