Semaphore timeout period has expired

What does this message mean. I've run a deep scan of my old HHD, trying to recover video and music files from it. I ran the free version of Recuva and has found all of these files and notes that they all are in excellent condition and none have been overwritten. I've selected the files I wished to recover and pressed recover, the program goes through the motions of transferring the files but then notes that no files are transferred as the semaphore timeout period has expired. What is it and how do I work round it. Many thanks in advance Rob

You are recovering the files to a different drive aren't you?

What kind of drive are you using to recover to?

Try running a chkdsk as admin on the drive you are recovering to first.