I have a qlikview instance running, and it loads data every 15 minutes.  Every couple of weeks, there's an issue.  I get the following: "System error: Failed to open file in write mode for file".   The files are all available.  I found what I have to do is open up the impacted files, and them write them to a new file.  then my data load scripts work fine.

the question is why does this happen and how can I prevent it?  It's frustrating for me and my user base