Thank you for the replies, we do a lot of Arri Alexa and DLSR footage back ups and there has been recently a significant of .DS store errors. I was told by the Retrospect tech support that the error is to be ignored so that maybe what is eating up the tape and causing it to spit out early. Also we have been in contact with HP support or our LTO 4 deck and the diagnostic we got back from them is that the machine has been cleaned "too much" and is needing replaced. So that is where we are at. Thank you again for the input.
With my last few backup attempts, the tape has not been holding the full capacity of the tape size and ejects informing it is full and needs an second tape to finish the backup. Yesterday I started a 653G backup, put an LTO 4 tape in that holds 800G uncompressed. Today the backup had written 492G and had ejected with 161G remaining and needed a new tape to finish the backup. Not sure why this is happening. Thoughts anyone?? Thanks! Retrospect v 6.1.126