Force Disk Usage Refresh on QNAP
 

I can't tell you how many times I have looked at the resources page of my QNAP
NAS only to be left wondering how much space I have left after some large
transfers. Unfortunately, QNAP did not build in a manual refresh option for
the storage on your NAS. As always, there are a couple of ways you can do this.

http://computingondemand.com/article...fresh-on-qnap/