Copying starts fine but at the last "15 minutes remaining" to finish point, the copying stalls and Windows puts up a popup saying it couldn't find the object to copy. When I try to go elsewhere in the nexus file structure I discover the connection has been lost and Windows can no longer see the nexus 5 files. So I need to shut down the laptop to safely disconnect the nexus.
This happens repeatedly. Smaller folders copied fine.
Is this because there is something special about twrp nandroid backup files that make them uncopyable, or could this mean there is a corrupt file or something else?
What should I do?