VM storage full

Hello,

We have a VM fortianalyzer 6.2 which shows on the widget that the VM storage is full i.e. 500GB out of 500GB. Is that even possible?

Since we are planning to upgrade it to 6.4 and our firewalls to 6.4.6, I am worried about this red bar on the fortianalyzer widget. 

Note that the fortianalyzer is licensed for 500GB, 1GB/day, the current use is around 15%.

Also, if you have any idea about compatibility issues with 6.4.6 firewalls, please let me know.

Thanks a lot.