There are expired or expiring licenses in your inventory.
2. When clicked on Manage your licenses, see that Evaluation license is expired.
3. Remove license option is greyed out:
If the license is though expired but if assigned to any asset in inventory, remove option will be greyed out.
1. Go to Menu > Administration > licenses tab
2. Expand evaluation license, check in tabs if this license is assigned to any vCenter\hosts\vSAN cluster\supervisors or solutions.
3. If it is assigned, replace it with valid license and then remove expired license from inventory.
Note: If the hosts that have the license applied to are to be decommissioned, remove them from inventory from the vCenter and then the remove option should be available again.