I got this error when trying to create a datastore on a local SSD I had just installed:
A specified parameter was not correct.
This blog post reported it’s a problem with having an existing MBR partition on the disk.
Apparently, VMFS5 doesn’t like that scenario. Usually, you’d have to manually delete the partition via some shell commands on the ESXi host. But, one of the comments mentioned they were able to create a VMFS3 partition first, and then upgrade it to VMFS5. Worked for me 🙂