I tried to update a VMware host through update manager and I got the below error through stage and remediation.
VMware indicates that:
This issue occurs if the /locker/ folder contains too many files aside from the /locker/packages (or /store/packages) folder. Remediation cannot happen as the disk does not have enough space.
/locker partition is the local Datastore of the host and in my case did not contain a lot of data except from the directory of packages.
The solution for this error was to remediate less updates and not all of them once. For example I could remediate 28 patches, but I performed that in two waves 14 on each iteration.