diff --git a/builder/proxmox/clone/builder.go b/builder/proxmox/clone/builder.go
index 0e21f05b6..8f088f81d 100644
--- a/builder/proxmox/clone/builder.go
+++ b/builder/proxmox/clone/builder.go
@@ -54,7 +54,7 @@ func (*cloneVMCreator) Create(vmRef *proxmoxapi.VmRef, config proxmoxapi.ConfigQ
 	comm := state.Get("comm").(*communicator.Config)
 
 	fullClone := 1
-	if c.FullClone == false {
+	if c.FullClone.False() {
 		fullClone = 0
 	}
 
diff --git a/builder/proxmox/clone/config.go b/builder/proxmox/clone/config.go
index 0fce27b4e..e9a8721d6 100644
--- a/builder/proxmox/clone/config.go
+++ b/builder/proxmox/clone/config.go
@@ -4,14 +4,15 @@ package proxmoxclone
 
 import (
 	proxmox "github.com/hashicorp/packer/builder/proxmox/common"
+	"github.com/hashicorp/packer/helper/config"
 	"github.com/hashicorp/packer/packer"
 )
 
 type Config struct {
 	proxmox.Config `mapstructure:",squash"`
 
-	CloneVM   string `mapstructure:"clone_vm"`
-	FullClone bool   `mapstructure:"full_clone"`
+	CloneVM   string         `mapstructure:"clone_vm"`
+	FullClone config.Trilean `mapstructure:"full_clone" required:"false"`
 }
 
 func (c *Config) Prepare(raws ...interface{}) ([]string, []string, error) {
diff --git a/builder/proxmox/clone/config.hcl2spec.go b/builder/proxmox/clone/config.hcl2spec.go
index 4c946c17f..879549542 100644
--- a/builder/proxmox/clone/config.hcl2spec.go
+++ b/builder/proxmox/clone/config.hcl2spec.go
@@ -100,7 +100,7 @@ type FlatConfig struct {
 	AdditionalISOFiles        []proxmox.FlatstorageConfig `mapstructure:"additional_iso_files" cty:"additional_iso_files" hcl:"additional_iso_files"`
 	VMInterface               *string                     `mapstructure:"vm_interface" cty:"vm_interface" hcl:"vm_interface"`
 	CloneVM                   *string                     `mapstructure:"clone_vm" cty:"clone_vm" hcl:"clone_vm"`
-	FullClone                 *bool                       `mapstructure:"full_clone" cty:"full_clone" hcl:"full_clone"`
+	FullClone                 *bool                       `mapstructure:"full_clone" required:"false" cty:"full_clone" hcl:"full_clone"`
 }
 
 // FlatMapstructure returns a new FlatConfig.