dunno if anyone else has had this problem but i lost one of my tunes the other night due to a cpu crash wile saving .
thought i’d lost it for good till i opened up the xrns with winrar and used the fix archive tool .
sorted it out compleatly 
most underapreciated yet wholely life saving tip award goes too…
You’re a hero… 
turn on the autobackup function in the preferences instead.
Interesting, thanks!
I had a corrupt xrns due to disconnection during download, and resuming download after reconnecting. This worked for that too.
Why not letting WinRAR do the magic itself? Everyone has this tool.