Skyrim Mod:Save File Format

See File Format Conventions to understand the variables and the data types this specification uses.

FormID

FormIDs in save files are stored as 3 bytes, rather than the usual 4 byte uint32 formID. These will be referred to as RefID.

RefID

The lower 22 bits represent the formID value itself, while the upper 2 bits are the type of formID.

Name	Type/Size	Info
byte0	uint8	The upper two bits represent the type of formID: 0 = An index into the File.formIDArray. If the index value of 0 is given, the formID is 0x00000000, else, index into the array using value - 1. 1 = Default (i.e., came from Skyrim.esm) 2 = Created (i.e., plugin index of 0xFF) 3 = ???
byte1	uint8
byte2	uint8

For example, the global variable "DragonsAbsorbed" (0x0001C0F2) becomes the bytes: 41 C0 F2

File

Name	Type/Size	Info
magic	char[13]	Constant: "TESV_SAVEGAME"
headerSize	uint32	Size of the header.
header	Header
screenshotData	LE: uint8[3*shotWidth*shotHeight] SE: uint8[4*shotWidth*shotHeight]	For LE: RGB pixel data of the image. For SE: RGBA pixel data of the image.
uncompressedLen	uint32	Uncompressed length (SE only). Appears only If compression is present.
compressedLen	uint32	Compressed length (SE only). Appears only If compression is present.
formVersion	uint8	current as of LE 1.9 and SE 1.5.97 is 74.
pluginInfoSize	uint32	Size of the plugin information.
pluginInfo	Plugin Info
lightPluginInfo	Light Plugin Info	Only for SE save games (and formVersion >= 78?). This contains info about ESL plugins.
fileLocationTable	File Location Table
globalDataTable1	Global Data[fileLocationTable.globalDataTable1Count]	Types 0 to 8.
globalDataTable2	Global Data[fileLocationTable.globalDataTable2Count]	Types 100 to 114.
changeForms	Change Form[fileLocationTable.changeFormCount]
globalDataTable3	Global Data[fileLocationTable.globalDataTable3Count]	Types 1000 to 1005.
formIDArrayCount	uint32
formIDArray	formID[formIDArrayCount]	Not to be confused with RefIDs. These are FormIDs, four bytes in length, little endian.
visitedWorldspaceArrayCount	uint32
visitedWorldspaceArray	formID[visitedWorldspaceArrayCount]	A list of the FormIDs of all worldspaces visited by the player.
unknown3TableSize	uint32	Size in bytes of unknown3Table.
unknown3Table	Unknown 3 Table

Header

Name	Type/Size	Info
version	uint32	Current LE version: 9, supported: 7 - 9, for SE it will be 12. Use this to determine whether or not the save file is for LE or SE.
saveNumber	uint32	Save number, used for default name of save file. Presumably this is a counter keeping track of the total number of saves you have made to date.
playerName	wstring
playerLevel	uint32
playerLocation	wstring
gameDate	wstring	In-game date at the time of saving.
playerRaceEditorId	wstring
playerSex	uint16	0 = Male 1 = Female
playerCurExp	float32	Experience gathered for level up.
playerLvlUpExp	float32	Experience required for level up.
filetime	FILETIME	See the Microsoft Docs for more info on this type.
shotWidth	uint32	Screenshot width (in pixels).
shotHeight	uint32	Screenshot height (in pixels).
compressionType	uint16	(SE only) 0 = None 1 = zLib (appears to not be used, see this from MO2. It seems however to be used for Change Forms) 2 = LZ4 (Block format) If compression is present, everything after the compression lengths is compressed.

Plugin Info

Name	Type/Size	Info
pluginCount	uint8
plugins	wstring[pluginCount]

Light Plugin Info

Note: only found in SE save games

Name	Type/Size	Info
pluginCount	uint16
plugins	wstring[pluginCount]

File Location Table

Name	Type/Size	Info
formIDArrayCountOffset	uint32	Absolute offset to the start of File.formIDArrayCount.
unknownTable3Offset	uint32	Absolute offset to the start of File.unknown3TableSize.
globalDataTable1Offset	uint32	Absolute offset to the start of File.globalDataTable1.
globalDataTable2Offset	uint32	Absolute offset to the start of File.globalDataTable2.
changeFormsOffset	uint32	Absolute offset to the start of File.changeForms.
globalDataTable3Offset	uint32	Absolute offset to the start of File.globalDataTable3.
globalDataTable1Count	uint32	The number of Global Data in File.globalDataTable1 (9).
globalDataTable2Count	uint32	The number of Global Data in File.globalDataTable2 (15).
globalDataTable3Count	uint32	The number of Global Data in File.globalDataTable3 (5 -- bugged). Note: This count is currently bugged (as of version 112) that it does not include type 1001 (Papyrus) in the count. This causes Skyrim to never read the final type in this table, which is typically type 1005 (Main), thankfully the bug is harmless since this type never has any data.
changeFormCount	uint32
unused	uint32[15]

Global Data

Name	Type/Size	Info
type	uint32
length	uint32
data	uint8[length]	Format of data depends on its type: 0 = Misc Stats 1 = Player Location 2 = TES 3 = Global Variables 4 = Created Objects 5 = Effects 6 = Weather 7 = Audio 8 = SkyCells 100 = Process Lists 101 = Combat 102 = Interface 103 = Actor Causes 104 = Unknown 104 105 = Detection Manager 106 = Location MetaData 107 = Quest Static Data 108 = StoryTeller 109 = Magic Favorites 110 = PlayerControls 111 = Story Event Manager 112 = Ingredient Shared 113 = MenuControls 114 = MenuTopicManager 1000 = Temp Effects 1001 = Papyrus 1002 = Anim Objects 1003 = Timer 1004 = Synchronized Animations 1005 = Main

Change Form

Note: the layout of the data section is not a Record as it is in a mod file. Work is in progress documenting changeForm structures here: changeFlags

Name	Type/Size	Info
formID	RefID
changeFlags	uint32	A combination of changeFlags that indicates which changes are included in the data.
type	uint8	Upper 2 bits represent the size of the data lengths: 0 = uint8 1 = uint16 (> 0xFF) 2 = uint32 (> 0xFFFF) Lower 6 bits represent the type of form: 0 = 63 (REFR) REFR change form 1 = 64 (ACHR) ACHR change form 2 = 65 (PMIS) 3 = 67 (PGRE) 4 = 68 (PBEA) 5 = 69 (PFLA) 6 = 62 (CELL) 7 = 78 (INFO) 8 = 79 (QUST) QUST change form 9 = 45 (NPC_) NPC_ change form 10 = 25 (ACTI) 11 = 26 (TACT) 12 = 27 (ARMO) 13 = 28 (BOOK) 14 = 29 (CONT) 15 = 30 (DOOR) 16 = 31 (INGR) 17 = 32 (LIGH) 18 = 33 (MISC) 19 = 34 (APPA) 20 = 35 (STAT) 21 = 37 (MSTT) 22 = 42 (FURN) 23 = 43 (WEAP) 24 = 44 (AMMO) 25 = 47 (KEYM) 26 = 48 (ALCH) 27 = 49 (IDLM) 28 = 50 (NOTE) 29 = 105 (ECZN) 30 = 10 (CLAS) 31 = 11 (FACT) 32 = 81 (PACK) 33 = 75 (NAVM) 34 = 120 (WOOP) 35 = 19 (MGEF) 36 = 115 (SMQN) 37 = 124 (SCEN) 38 = 106 (LCTN) 39 = 123 (RELA) 40 = 72 (PHZD) 41 = 71 (PBAR) 42 = 70 (PCON) 43 = 93 (FLST) FLST change form 44 = 46 (LVLN) 45 = 55 (LVLI) 46 = 84 (LVSP) 47 = 66 (PARW) 48 = 22 (ENCH)
version	uint8	Current as of Skyrim 1.9 is 74. Older values (57, 64, 73) are also valid.
length1	depends on flags	Length of following data.
length2	depends on flags	If this value is non-zero, data is compressed (ZLib, so far tested on SE only). This value then represents the uncompressed length.
data	uint8[length1]

Unknown 3 Table

Name	Type/Size	Info
count	uint32
unknown	wstring[count]

Xbox 360

The Xbox 360 uses a container for all of its user content. The STFS file system used for the container has been mapped out and files within them can be extracted using tools such as WxPirs or Horizon.

It is entirely possible to use Xbox 360 game saves on the PC version of Skyrim. The only draw back is that the first time a game save is used on the PC version of the game, the preview screenshot is swizzled. Saving the game again once you have it loaded will fix this.

To get your XBOX 360 save. One would use a tool like Horizon to get your game save off of a Xbox 360 formatted drive (such as a USB drive) and extract the Savegame.dat from the Xbox 360 container and rename it to anything ending in ".ess". After this one would put this new ess file in Documents\My Games\Skyrim\Saves and load it in Skyrim as usual.

It is possible to perform this in the reverse direction as well. Rename your savegame.ess to savegame.dat. Then, use Horizon to reinject the save into the save originally transferred from the Xbox 360. You must then rehash and resign your save so it can be used on your Xbox 360. The only drawback of this is the same as the other: the screenshot is swizzled, but it works. This can be used to fix quest related bugs with the console if you have access to both a PC and Xbox 360 version of the game.