diff --git a/builder/proxmox/common/step_start_vm.go b/builder/proxmox/common/step_start_vm.go
index 6d6e2336..0d448eca 100644
--- a/builder/proxmox/common/step_start_vm.go
+++ b/builder/proxmox/common/step_start_vm.go
@@ -287,12 +287,12 @@ func generateProxmoxDisks(disks []diskConfig) proxmox.QemuDevices {
 		if devs[idx]["type"] == "scsi" || devs[idx]["type"] == "virtio" {
 			setDeviceParamIfDefined(devs[idx], "iothread", strconv.FormatBool(disks[idx].IOThread))
 		}
-		// Proxmox API expects the value of discard to be either "off" or "on"
+		// Proxmox API expects the value of discard to be either "on" or "ignore"
 		setDeviceParamIfDefined(devs[idx], "discard", func() string {
 			if disks[idx].Discard {
 				return "on"
 			}
-			return "off"
+			return "ignore"
 		}())
 		setDeviceParamIfDefined(devs[idx], "ssd", strconv.FormatBool(disks[idx].IOThread))
 	}