vCenter Server disk partitions on Windows or Linux are at 100% (i.e. the / partition)
This is due to previously gathered support bundles in one of the following locations:
vCenter Server Appliance:
/etc/vmware-vpx/docRoot/diagnostics OR /etc/vmware-vpx/bundle-stage
vCenter on Windows:
C:\ProgramData\VMware\vCenterServer\cfg\vmware-vpx\docRoot\diagnostics
Manually delete the support bundles in the previously mentioned directories. After deleting the bundles, there should be space on the partition.