HOWTO Reinstall Skyrim SE 1.5.97 if you don't have a backup

[Mousetick]

Update: There is an alternate procedure now available, using a binary patcher to downgrade an existing Steam installation (English only) of Skyrim version 1.6.318 back to 1.5.97. On Nexus: Unofficial Skyrim Special Edition Downgrade Patcher. I haven't tried it so can't vouch for it, but it's easier to use and smaller to download than the following.

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The following procedure allows you to download from Steam and install a pristine vanilla copy of the last Skyrim SE version (1.5.97) before it was updated to Skyrim AE (1.6.317 or greater). It assumes some familiarity with the Windows command line (cmd.exe).

It relies on a 3rd-party tool, the depot downloader. The procedure and the tool are safe to use, legit and allowed as long as you own the game on Steam. They are however unsupported by Steam, so don't go ask Steam for support if you encounter any issue.

First you need to decide where you want to install the game. Choose a location with enough storage space, that is outside any Steam library folder. Let's call this location <installation-folder>. For example, it could be 'D:\Game\Skyrim SE Custom'.

Second, download the Depot Downloader zip file and extract it wherever you like. Let's call the extracted folder <depot-downloader-folder>.

Third, open a Windows command window (cmd.exe).

Enter the following commands, one by one, substituting <depot-downloader-folder> and <installation-folder> by the actual full path to their respective folder, <steam-username> and <steam-password> by your Steam account username and password, respectively. If you're using Steam Guard, enter the 2FA code when prompted by each invocation of the depot downloader.

cd <depot-downloader-folder>
dotnet DepotDownloader.dll -app 489830 -depot 489831 -manifest 7848722008564294070 -dir <installation-folder> -username <steam-username> -password <steam-password>
dotnet DepotDownloader.dll -app 489830 -depot 489832 -manifest 8702665189575304780 -dir <installation-folder> -username <steam-username> -password <steam-password>
dotnet DepotDownloader.dll -app 489830 -depot 489833 -manifest 2289561010626853674 -dir <installation-folder> -username <steam-username> -password <steam-password>

The depot downloader will display some messages to show progress.

If you need a localized version in a language other than English, enter the following 5th command to download and install a language pack, substituting <depot-id> and <manifest-id> respectively with their corresponding ids for your desired language. This is for information only, I haven't actually verified that they work or are correct:

• French: 489834 6504731950971590957
• Italian: 489835 4512087029950241124
• German: 489836 7673013291267519904
• Spanish: 489837 3708515970164396161
• Russian: 489838 6206633033379583541
• Polish: 489839 1778665308409252011
• Chinese: 544860 827369994814912743
• Japanese: 544861 2572676613884548532

dotnet DepotDownloader.dll -app 489830 -depot <depot-id> -manifest <manifest-id> -dir <installation-folder> -username <steam-username> -password <steam-password>

 

Once the last command above has completed, Skyrim SE 1.5.97 is ready to use in <installation-folder>. Now you may want to trash <depot-downloader-folder> if you want as it's no longer needed.

 

This procedure can be used with any game. It's used a lot for example by Speedrunners who rely on specific versions of a game to leverage glitches and exploits before they were patched. Steam app ids, depot ids, and manifest ids for all Steam games and different versions can be found on SteamDB.

Further info: depot downloader on GitHub; general purpose guide on how to use depot downloader to downgrade Steam games How to Downgrade or Change the Version of a Game.

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Related (added by z929669): Running two SSE versions on the same box. Also see Mousetick's instructions.

 

[Mousetick]

Addendum: If you're going to use the installation above as a foundation for modding, you'll need to manually configure some tools (e.g. ModOrganizer, BethINI, ...) to specify your custom <installation-folder> otherwise they'll try to auto-detect it automatically and pick the wrong location within the Steam library folder.

[Decopauge123]

Thank you very much for this!  I was starting to think that a rotating inclined plane had been applied to me when I first read that the SkyrimSE v1.0.0 guide wasn't compatible with Skyrim AE (which I of course purchased as soon as I saw it)..

Edited November 15, 2021 by Decopauge123

[Akatosh]

Is this really safe to use? Using your personal log-in data in a 3rd-party tool just seems so..risky.

[DoubleYou]

Just download Enderal Special Edition and copy the SkyrimSE.exe and bink dll.

[Mousetick]

1 hour ago, Akatosh said:

Is this really safe to use? Using your personal log-in data in a 3rd-party tool just seems so..risky.

Excellent question to ask with all the malicious crap circulating nowadays. The version of Depot Downloader I linked to is authentic and safe to use. It asks for Steam account credentials and passes them on to the Steam servers because Steam needs to verify you have a license and are authorized to download the packages. No one has had their Steam account hijacked by using this tool yet, as far as I know.

But you don't have to trust me as I'm just a random nobody on the internet. If you have the technical know-how and are so inclined, you can examine the source code available on GitHub, and/or build the tool from source, and/or monitor the network activity of the tool, to verify that it doesn't do anything with the account credentials other than transmitting them to Steam.

So if you're still in doubt, don't take any risk or waste any time. Instead opt for another solution, i.e. Unofficial Patcher or Enderal SE. Each one has their pros and cons.

Hope this helps.

[DrSudoku]

Feeling a bit dumb... but how do I launch from the new files? When I try launching directly it connects to Steam and tries to launch an installer, do I just copy all the files into a normal folder in my Steam library folder and then launch from Steam as normal with updates disabled?

[Mousetick]

5 hours ago, DrSudoku said:

Feeling a bit dumb... but how do I launch from the new files? When I try launching directly it connects to Steam and tries to launch an installer, do I just copy all the files into a normal folder in my Steam library folder and then launch from Steam as normal with updates disabled?

There are several options depending on what you want to do, and how comfortable you are with tweaking configuration settings in various pieces of software.

Below is one option. Not necessarily the most convenient, but arguably the easiest:

• I'm assuming your regular installation of Skyrim SE has been updated by Steam to 1.6.x (aka Anniversary Edition). If that's not the case, keep your side copy of Skyrim SE 1.5.97 where it is for the time being, and download/install/update the latest Skyrim AE version using the Steam client normally. At this point, your Steam installation of Skyrim SE/AE is up to date (1.6.323).
• Rename the up-to-date Skyrim AE folder within your Steam library folder: 'Skyrim Special Edition' to 'Skyrim Anniversary Edition'.
• Copy (preferably, so you always have a backup) or move your side installation of Skyrim SE 1.5.97 to your Steam library folder and name the folder 'Skyrim Special Edition'.
• At this point you have 2 Skyrim folders sitting side-by-side within your Steam library folder: 'Skyrim Special Edition' containing Skyrim SE 1.5.97, and 'Skyrim Anniversary Edition' containing Skyrim SE/AE 1.6.323.
• Now you should be able to launch the (old 1.5.97) Skyrim SE game from anywhere (e.g. from Steam client, Windows Explorer, Mod Organizer...) and not be prompted by Steam. Keep automatic updates disabled from Steam.
• If you want to launch the (new 1.6.x) Skyrim AE game, you'll need to do the game folder switcheroo in reverse within your Steam library folder. I.E. rename 'Skyrim Special Edition' to 'Skyrim SE Backup' and rename 'Skyrim Anniversary Edition' to 'Skyrim Special Edition'. But be careful to keep track of which folder actually contains what.

Other options are discussed in another topic, starting here. You can read that if you want.

Feel free to ask if anything is unclear.

Edited December 4, 2021 by Mousetick

[BlkJeff]

On 12/3/2021 at 8:22 PM, Mousetick said:

There are several options depending on what you want to do, and how comfortable you are with tweaking configuration settings in various pieces of software.

Below is one option. Not necessarily the most convenient, but arguably the easiest:

• I'm assuming your regular installation of Skyrim SE has been updated by Steam to 1.6.x (aka Anniversary Edition). If that's not the case, keep your side copy of Skyrim SE 1.5.97 where it is for the time being, and download/install/update the latest Skyrim AE version using the Steam client normally. At this point, your Steam installation of Skyrim SE/AE is up to date (1.6.323).
• Rename the up-to-date Skyrim AE folder within your Steam library folder: 'Skyrim Special Edition' to 'Skyrim Anniversary Edition'.
• Copy (preferably, so you always have a backup) or move your side installation of Skyrim SE 1.5.97 to your Steam library folder and name the folder 'Skyrim Special Edition'.
• At this point you have 2 Skyrim folders sitting side-by-side within your Steam library folder: 'Skyrim Special Edition' containing Skyrim SE 1.5.97, and 'Skyrim Anniversary Edition' containing Skyrim SE/AE 1.6.323.
• Now you should be able to launch the (old 1.5.97) Skyrim SE game from anywhere (e.g. from Steam client, Windows Explorer, Mod Organizer...) and not be prompted by Steam. Keep automatic updates disabled from Steam.
• If you want to launch the (new 1.6.x) Skyrim AE game, you'll need to do the game folder switcheroo in reverse within your Steam library folder. I.E. rename 'Skyrim Special Edition' to 'Skyrim SE Backup' and rename 'Skyrim Anniversary Edition' to 'Skyrim Special Edition'. But be careful to keep track of which folder actually contains what.

Other options are discussed in another topic, starting here. You can read that if you want.

Feel free to ask if anything is unclear.

Hey there. Thanks for your efforts during this weird transition. 

II'm doing a fresh install of STEP after some time, having decided to come back right before the update drama. 'm using the method of creating two folders (SAE and SSE), having downloaded 1.5.97 using depot downloader. After creating a new instance in MO2, and resetting every tool in the guide with updated file paths, I'm experiencing a weird problem. I am at Step 3 of the guide, and it seems that Update.esm is not seen by MO2 or LOOT, despite being present in the 'Data' folder of the SSE installation. Any idea what I may have missed?

 

[z929669]

11 minutes ago, BlkJeff said:

Hey there. Thanks for your efforts during this weird transition. 

II'm doing a fresh install of STEP after some time, having decided to come back right before the update drama. 'm using the method of creating two folders (SAE and SSE), having downloaded 1.5.97 using depot downloader. After creating a new instance in MO2, and resetting every tool in the guide with updated file paths, I'm experiencing a weird problem. I am at Step 3 of the guide, and it seems that Update.esm is not seen by MO2 or LOOT, despite being present in the 'Data' folder of the SSE installation. Any idea what I may have missed?

You should not need different file paths for any MO-integrated tools if you install into a neutral location as we described in the System Setup Guide in Step 2.

Once you have tricked Steam into thinking you have the latest version of the game, you simply need to rename the game folders. It sounds like you are using dedicated names of "Skyrim Special Edition-SAE" and "Skyrim Special Edition-SSE". So that means double the config, double the potential for issues, and double the headache.

If you only use "Skyrim Special Edition" at any given time, then it's all much simpler. Just rename the Steam-game instance you want to use to "Skyrim Special Edition" and leave the other one named "Skyrim Special Edition-SxE". This way MO, tools and Steam only see and recognize one game folder at any given time. You really only need to configure BethINI for each instance when you want to use it.

[BlkJeff]

8 minutes ago, z929669 said:

You should not need different file paths for any MO-integrated tools if you install into a neutral location as we described in the System Setup Guide in Step 2.

Once you have tricked Steam into thinking you have the latest version of the game, you simply need to rename the game folders. It sounds like you are using dedicated names of "Skyrim Special Edition-SAE" and "Skyrim Special Edition-SSE". So that means double the config, double the potential for issues, and double the headache.

If you only use "Skyrim Special Edition" at any given time, then it's all much simpler. Just rename the Steam-game instance you want to use to "Skyrim Special Edition" and leave the other one named "Skyrim Special Edition-SxE". This way MO, tools and Steam only see and recognize one game folder at any given time. You really only need to configure BethINI for each instance when you want to use it.

Right, that's why it's perplexing. I assure you, I only have one folder named Skyrim Special Edition.

[z929669]

19 minutes ago, BlkJeff said:

Right, that's why it's perplexing. I assure you, I only have one folder named Skyrim Special Edition.

But you posted this:

Quote

After creating a new instance in MO2, and resetting every tool in the guide with updated file paths, I'm experiencing a weird problem.

There are no file paths to change if you use the same exact tools and the same exact game folder name for each version.

You also need to launch both versions with the launcher on first launch to establish proper reg and INI settings.

Check your game folders to ensure that they have all of the correct game files and that EXEs are correct versions (right-click > properties)

[BlkJeff]

1 hour ago, z929669 said:

But you posted this:

There are no file paths to change if you use the same exact tools and the same exact game folder name for each version.

You also need to launch both versions with the launcher on first launch to establish proper reg and INI settings.

Check your game folders to ensure that they have all of the correct game files and that EXEs are correct versions (right-click > properties)

Okay. I mispoke. I reset/reinstalled every tool to make sure the paths were correct. I have validated the steam files. After initializing that launcher, I renamed the game folder to 'Skyrim Anniversary Edition'. I then moved my backup of 1.5.97 into the steamapps/common/ folder  under the name 'Skyrim Special Edition'. I checked everything twice before coming back. For some reason MO2 does not see update.esm

I'm acknowledging wrong here, just trying to figure it out. 

edit: to clarify, Update.esm is in the plugins pane on the right, but not listed as a mod on the left. 

Edited December 13, 2021 by BlkJeff

[Mousetick]

12 minutes ago, BlkJeff said:

edit: to clarify, Update.esm is in the plugins pane on the right, but not listed as a mod on the left. 

It's ok. It's not supposed to show up on the left  Technically it's not a "mod", it's part of the base game. Only the Skyrim SE DLCs are shown in the left pane. If you have all the vanilla .esm  plugins showing in the right pane, it looks like you're good to go.

[Arel]

I am getting System.Exception: Can't patch file, it doesn't match the expected format error with the patch, I have tried check integrity with steam but it didn't helped either. What can I do?