When upgrading Network Insight 6.7 to Patch 4 due to this security risk i ran into failures with insufficient disk space. After a bit of research i thought the minimum disk space of 2TB was not met for the appliance (due to previous upgrades) so i added disks to get to that and all lights in the infrastructure page turned green. Then retried the patch (from LCM) and that failed again with the same message so i started searching google for answers and came across this one : https://kb.vmware.com/s/article/88977
That was the exact problem i had, turned out there was 1 old upgrade directory in my vg-root once i removed that i could install the patch without any problems.
The original article was posted on: www.hollebollevsan.nl