diff --git a/docs/resources/vm_qemu.md b/docs/resources/vm_qemu.md
index 00bcbc36..2977dd1f 100644
--- a/docs/resources/vm_qemu.md
+++ b/docs/resources/vm_qemu.md
@@ -190,7 +190,7 @@ Due to the complexity of the `disk` block, there is a settings matrix that can b
 |`discard`             |`bool`  |`false`|Controls whether to pass discard/trim requests to the underlying storage. Only effective when the underlying storage supports thin provisioning. There are other caveats too, see the [docs about disks](https://pve.proxmox.com/pve-docs/chapter-qm.html#qm_hard_disk) for more info.|
 |`disk_file`           |`string`|       |The path to the disk file. **Required** when `type`=`disk` and `passthrough`=`true`|
 |`emulatessd`          |`bool`  |`false`|Whether to expose this drive as an SSD, rather than a rotational hard disk.|
-|`format`              |`string`|`raw`  |The drive’s backing file’s data format.|
+|`format`              |`string`|`raw`  |The drive’s backing file’s data format. Default only applies when `type`=`disk` and `passthrough`=`false`|
 |`id`                  |`int`   |       |**Computed** Unique id of the disk.|
 |`iops_r_burst`        |`int`   |`0`    |Maximum number of iops while reading in short bursts. `0` means unlimited.|
 |`iops_r_burst_length` |`int`   |`0`    |Length of the read burst duration in seconds. `0` means the default duration dictated by proxmox.|
diff --git a/proxmox/resource_vm_qemu.go b/proxmox/resource_vm_qemu.go
index 5eee493d..7ba9b247 100755
--- a/proxmox/resource_vm_qemu.go
+++ b/proxmox/resource_vm_qemu.go
@@ -493,7 +493,7 @@ func resourceVmQemu() *schema.Resource {
 						"discard":              {Type: schema.TypeBool, Optional: true},
 						"disk_file":            schema_PassthroughFile(schema.Schema{Optional: true}),
 						"emulatessd":           {Type: schema.TypeBool, Optional: true},
-						"format":               schema_DiskFormat(),
+						"format":               schema_DiskFormat(schema.Schema{}),
 						"id":                   schema_DiskId(),
 						"iops_r_burst":         schema_DiskBandwidthIopsBurst(),
 						"iops_r_burst_length":  schema_DiskBandwidthIopsBurstLength(),
@@ -2105,9 +2105,10 @@ func mapToTerraform_Memory(config *pxapi.QemuMemory, d *schema.ResourceData) {
 // nil check is done by the caller
 func mapToTerraform_QemuCdRom_Disk_unsafe(config *pxapi.QemuCdRom) map[string]interface{} {
 	return map[string]interface{}{
-		"type":        "cdrom",
+		"backup":      true, // always true to avoid diff
+		"iso":         mapFormStruct_IsoFile(config.Iso),
 		"passthrough": config.Passthrough,
-		"iso":         mapFormStruct_IsoFile(config.Iso)}
+		"type":        "cdrom"}
 }
 
 func mapToTerraform_QemuCdRom_Disks(config *pxapi.QemuCdRom) []interface{} {
@@ -2129,8 +2130,9 @@ func mapToTerraform_QemuCdRom_Disks(config *pxapi.QemuCdRom) []interface{} {
 // nil check is done by the caller
 func mapToTerraform_QemuCloudInit_Disk_unsafe(config *pxapi.QemuCloudInitDisk) map[string]interface{} {
 	return map[string]interface{}{
-		"type":    "cloudinit",
-		"storage": config.Storage}
+		"backup":  true, // always true to avoid diff
+		"storage": config.Storage,
+		"type":    "cloudinit"}
 }
 
 // nil pointer check is done by the caller
@@ -3227,7 +3229,7 @@ func mapToSDK_QemuIdeStorage_Disk(ide *pxapi.QemuIdeStorage, schema map[string]i
 				Cache:         pxapi.QemuDiskCache(schema["cache"].(string)),
 				Discard:       schema["discard"].(bool),
 				EmulateSSD:    schema["emulatessd"].(bool),
-				Format:        pxapi.QemuDiskFormat(schema["format"].(string)),
+				Format:        default_format(schema["format"].(string)),
 				Replicate:     schema["replicate"].(bool),
 				Serial:        pxapi.QemuDiskSerial(schema["serial"].(string)),
 				WorldWideName: pxapi.QemuWorldWideName(schema["wwn"].(string))}
@@ -3376,7 +3378,7 @@ func mapToSDK_QemuSataStorage_Disk(sata *pxapi.QemuSataStorage, schema map[strin
 				Cache:         pxapi.QemuDiskCache(schema["cache"].(string)),
 				Discard:       schema["discard"].(bool),
 				EmulateSSD:    schema["emulatessd"].(bool),
-				Format:        pxapi.QemuDiskFormat(schema["format"].(string)),
+				Format:        default_format(schema["format"].(string)),
 				Replicate:     schema["replicate"].(bool),
 				Serial:        pxapi.QemuDiskSerial(schema["serial"].(string)),
 				WorldWideName: pxapi.QemuWorldWideName(schema["wwn"].(string))}
@@ -3596,7 +3598,7 @@ func mapToSDK_QemuScsiStorage_Disk(scsi *pxapi.QemuScsiStorage, schema map[strin
 				Cache:         pxapi.QemuDiskCache(schema["cache"].(string)),
 				Discard:       schema["discard"].(bool),
 				EmulateSSD:    schema["emulatessd"].(bool),
-				Format:        pxapi.QemuDiskFormat(schema["format"].(string)),
+				Format:        default_format(schema["format"].(string)),
 				IOThread:      schema["iothread"].(bool),
 				ReadOnly:      schema["readonly"].(bool),
 				Replicate:     schema["replicate"].(bool),
@@ -3883,7 +3885,7 @@ func mapToSDK_QemuVirtIOStorage_Disk(virtio *pxapi.QemuVirtIOStorage, schema map
 				Bandwidth:     mapToSDK_QemuDiskBandwidth_Disk(schema),
 				Cache:         pxapi.QemuDiskCache(schema["cache"].(string)),
 				Discard:       schema["discard"].(bool),
-				Format:        pxapi.QemuDiskFormat(schema["format"].(string)),
+				Format:        default_format(schema["format"].(string)),
 				IOThread:      schema["iothread"].(bool),
 				ReadOnly:      schema["readonly"].(bool),
 				Replicate:     schema["replicate"].(bool),
@@ -4194,7 +4196,7 @@ func schema_Ide(slot string) *schema.Schema {
 							"cache":          schema_DiskCache(),
 							"discard":        {Type: schema.TypeBool, Optional: true},
 							"emulatessd":     {Type: schema.TypeBool, Optional: true},
-							"format":         schema_DiskFormat(),
+							"format":         schema_DiskFormat(schema.Schema{Default: "raw"}),
 							"id":             schema_DiskId(),
 							"linked_disk_id": schema_LinkedDiskId(),
 							"replicate":      {Type: schema.TypeBool, Optional: true},
@@ -4252,7 +4254,7 @@ func schema_Sata(slot string) *schema.Schema {
 							"cache":          schema_DiskCache(),
 							"discard":        {Type: schema.TypeBool, Optional: true},
 							"emulatessd":     {Type: schema.TypeBool, Optional: true},
-							"format":         schema_DiskFormat(),
+							"format":         schema_DiskFormat(schema.Schema{Default: "raw"}),
 							"id":             schema_DiskId(),
 							"linked_disk_id": schema_LinkedDiskId(),
 							"replicate":      {Type: schema.TypeBool, Optional: true},
@@ -4310,7 +4312,7 @@ func schema_Scsi(slot string) *schema.Schema {
 							"cache":          schema_DiskCache(),
 							"discard":        {Type: schema.TypeBool, Optional: true},
 							"emulatessd":     {Type: schema.TypeBool, Optional: true},
-							"format":         schema_DiskFormat(),
+							"format":         schema_DiskFormat(schema.Schema{Default: "raw"}),
 							"id":             schema_DiskId(),
 							"iothread":       {Type: schema.TypeBool, Optional: true},
 							"linked_disk_id": schema_LinkedDiskId(),
@@ -4370,7 +4372,7 @@ func schema_Virtio(setting string) *schema.Schema {
 							"backup":         schema_DiskBackup(),
 							"cache":          schema_DiskCache(),
 							"discard":        {Type: schema.TypeBool, Optional: true},
-							"format":         schema_DiskFormat(),
+							"format":         schema_DiskFormat(schema.Schema{Default: "raw"}),
 							"id":             schema_DiskId(),
 							"iothread":       {Type: schema.TypeBool, Optional: true},
 							"linked_disk_id": schema_LinkedDiskId(),
@@ -4546,22 +4548,20 @@ func schema_DiskCache() *schema.Schema {
 	}
 }
 
-func schema_DiskFormat() *schema.Schema {
-	return &schema.Schema{
-		Type:     schema.TypeString,
-		Optional: true,
-		Default:  "raw",
-		ValidateDiagFunc: func(i interface{}, k cty.Path) diag.Diagnostics {
-			v, ok := i.(string)
-			if !ok {
-				return diag.Errorf(errorString, k)
-			}
-			if err := pxapi.QemuDiskFormat(v).Validate(); err != nil {
-				return diag.FromErr(err)
-			}
-			return nil
-		},
+func schema_DiskFormat(s schema.Schema) *schema.Schema {
+	s.Type = schema.TypeString
+	s.Optional = true
+	s.ValidateDiagFunc = func(i interface{}, k cty.Path) diag.Diagnostics {
+		v, ok := i.(string)
+		if !ok {
+			return diag.Errorf(errorString, k)
+		}
+		if err := pxapi.QemuDiskFormat(v).Validate(); err != nil {
+			return diag.FromErr(err)
+		}
+		return nil
 	}
+	return &s
 }
 
 func schema_DiskId() *schema.Schema {
@@ -4676,6 +4676,9 @@ func warnings_CdromAndCloudinit(slot, kind string, schema map[string]interface{}
 	if schema["emulatessd"].(bool) {
 		diags = append(diags, warningDisk(slot, "emulatessd", "type", kind, ""))
 	}
+	if schema["format"].(string) != "" {
+		diags = append(diags, warningDisk(slot, "format", "type", kind, ""))
+	}
 	if schema["iops_r_burst"].(int) != 0 {
 		diags = append(diags, warningDisk(slot, "iops_r_burst", "type", kind, ""))
 	}
@@ -4728,8 +4731,18 @@ func warnings_CdromAndCloudinit(slot, kind string, schema map[string]interface{}
 }
 
 func warnings_DiskPassthrough(slot string, schema map[string]interface{}) diag.Diagnostics {
+	if schema["format"].(string) != "" {
+		return diag.Diagnostics{warningDisk(slot, "format", "type", "passthrough", "and slot = "+slot)}
+	}
 	if schema["storage"].(string) != "" {
 		return diag.Diagnostics{warningDisk(slot, "storage", "type", "passthrough", "and slot = "+slot)}
 	}
 	return diag.Diagnostics{}
 }
+
+func default_format(rawFormat string) pxapi.QemuDiskFormat {
+	if rawFormat == "" {
+		return pxapi.QemuDiskFormat("raw")
+	}
+	return pxapi.QemuDiskFormat(rawFormat)
+}