Question : How do I convert Thick to Thin on ESXi?

I have a few virtual machines setup to use Thick disks on ESXi when I didn't know better. I am building a new vm host server and want to move all virtual machines to the new server and use Thin Provisioning.

Can't seem to find out how to do that. :-(

Answer : How do I convert Thick to Thin on ESXi?

Two options

Install vCenter Server and use storage vmotion - that offers the ability to convert.
or
Use vCenter converter stand alone  to move your machines, you can resize the disks if needed as well as convert thick to thin

Good Luck