In VMware Horizon View VDI, when using floating pools with instant clones, you may run across a problem where VMs get the "Already Used" status after users log off. The VM remains unavailable for further use and does not get deleted or refreshed.
The reason for this usually is that some process is blocking the refresh/delete operation, causing the VM to remain unusable and powered on to allow a system administrator to investigate the issue. If this is not desired (e.g., the reason for the blockage is known but cannot be resolved immediately), there is a policy which can be set to allow for automatic clean up of these "dirty" VMs.
The attribute is called pae-DirtyVmPolicy and can be configured separately for each desktop pool:
The policy can be configured directly in LDAP through ADSI Edit.
After changing the attribute, the new policy is active immediately (i.e., no restart is necessary). If set to 2, all VMs in the "Already Used" state will be refreshed automatically after a minute or so.
More information and the original KB from VMware: https://kb.vmware.com/s/article/1000590