After having emptied a datastore on my vSphere cluster (using the Storage vMotion feature to hot move the virtual machines) I tried to delete it but I got the following error message:
The resource <datastore-id> is in use
Browsing the datastore, I wasn’t able to find any files that could explain why it was in use…
I had to disable the Storage I/O Control feature on that datastore and I was finally able to remove it: