If the “Save” button is greyed out when trying to add a hard disk in the ESXi web client, there could be several reasons for this issue. This post is to document one of the scenarios and illustrate the fix for it.
Scenario
1. Esxi 7.0 U2 virtual machine, no vCenter involved.
2. Add new hard disk in Web UI
3. The location of the new disk is in another volume/storage, because of “Hard disk 1” volume has no space left
4. “Save” Button is greyed out – can not save the configuration
Workaround
It feels like a Web UI bug from vsphere. The workaround is rather simple:
Firstly, try to configure a small disk on the volume that containing the first “Hard disk 1”, but NOT save it yet
Secondarily, browse the location to the new volume, in my case 1st HDD, and change the size of the new hard disk to what you want to allocate, you can see the “Save” button is still available.