SSE Conversions for LE Mods - Info & Guide

Some Skyrim LE mods work flawlessly with Skyrim SE, but some require conversion first. Converting an LE mod to SE is fairly easy, but it does take some time to do it properly. The Nexus has plenty of conversions and patches, but not all of them are done very well. Making a conversion that seem to work is fast & easy, but it can cause unforeseen errors after a certain amount of in-game hours, and even mess-up your savegame data. Making a proper conversion takes a while, but why risk messing up your savegame file?

Every single conversion/SE-patch in this guide has been made using the following method. No shortcuts or exceptions.
 

LE to SE Conversion Guide

Requirements:
SSE Creation Kit (LINK) *Full installation guide (LINK)
SSEEdit (LINK)
Bethesda Archive Extractor (LINK)
SSE NIF Optimizer (LINK)
NifSkope (LINK)


Preparation:
Open the Skyrim SE game-folder and edit "CreationKit.ini" with a notepad.
Make sure the following line is added, or you will not be able to open mods with multiple dependencies:

[General]
bAllowMultipleMasterLoads=1

I also recommend adding the following line to make using the Creation Kit significantly less annoying:

[MESSAGES]
bBlockMessageBoxes=1



Proper SSE Conversion:

First things first. Download the mod you want to convert. Create a folder named "Data", and unpack the mod into this folder, matching the structure of the Data folder inside the Skyrim SE game-folder. (Don't delete the LE mod-file after unpacking)
Following, I will refer to this folder as the "Conversion Data folder". You can now convert any file(s) needed before repacking the mod.
Note: If the mod ONLY contains textures, then no conversion is needed. You can use the mod as you would use any SE mod.

Correct Form ID (ESP):
If the mod contains ESP file(s), then these must be updated form Form ID 43 to Form ID 44. (Just changing the ID value in SSEEdit does NOT work)
Only the Creation Kit can properly do this.
1: Install the LE mod as you would usually install any SE mod. (Just don't launch the game)
2: Start the Creation Kit and click the "Load Master/Plugin Files" button.

Now you should see the Data window.

3: Double-click the ESP file you want to convert (checking the box), then click "Set as Active File" and finally click "OK".
*The Creation Kit will automatically select and load any Masters/dependencies needed for the ESP file.
The loading process will take some time. When you see an error massage, just click OK. Loading a mod typically generates 5 to 10 error messages. It looks crazy the first time, but just click OK to everything.
4: When the mod has been loaded, all you need to do is save the mod again. This will generate error messages as well. Just click OK to everything.
That's it. The Creation Kit has now saved the ESP file using the new Form ID format.
*Note: If you want to convert multiple ESP files, then you HAVE to close and restart the Creation Kit in between every file. The Creation Kit saves a bunch of cache that can cause problems if not cleared when switching files. ..Brilliant, I agree.
5: Copy the updated ESP file(s) into the conversion Data folder, and overwrite the old ESP file(s).
6: Uninstall the LE mod again.

Correct Form ID (ESM):
If the mod contains an ESM file, then the form ID must be updated in this file as well. Unfortunately you can't just load en ESM into the Creation Kit, so you need to change it to an ESP file first, update the ESP with the Creation Kit, and then change it back to ESM. ..Yes, brilliant.
1: Install the LE mod as you would install any SE mod. (Don't launch the game)
2: Start SSEEdit.
Select only the ESM file, then continue the loading process.
3: When the loader has finished, right click the mod and select "Apply filter for cleaning".
4: Wait .........
5: When the loader has finished, click the mod and select "File Header".

6: Edit the "Recorded Flags" and set it to "ESP".
7: Close SSEEdit. *It will automatically save the changes to the file.
8: Open the Skyrim SE game-folder, and open the Data folder.
9: Rename the ESM file to .esp instead.
10: Follow the process for updating ESP files to Form ID 44.
11: Use SSEEdit to change the flag back to ESM.
12: Rename the file back to .esm.
13: Copy the updated ESM file into the conversion Data folder, and overwrite the old ESM file.
14: Uninstall the LE mod again.

BSA files:
If the mod contains a BSA (Bethesda Archive) file, then it has to be unpacked.
1: Start Bethesda Archive Extractor.
2: Drag'n'drop the BSA and extract everything into the conversion Data folder. (Still keeping the correct file-structure)
3: Delete the BSA file. (Important - It's not only to save space. Skyrim will CTD if an old BSA is present)

NIF Conversion:
All NIF files must be converted/optimized.
1: Start SSE NIF Optimizer.
2: Brows to the folder containing the NIF files. (BUT PAY ATTENTION TO WHAT KIND OF NIF FILES)

Be very careful to check "Head Part Only" when optimizing head parts (Eyes, head, face-geom, hair), and leave it unchecked for ANY other file(s).
If a folder contains both "head parts" and "non-head parts", then you need to make a temporary folder and move all non-head parts out. Optimize the head parts, then change settings and optimize the non-head parts. Now move the non-head parts back into the original folder.
*The files WILL NOT WORK, if optimized with incorrect settings.

Invisible eye fix:
If the mod contains custom eye NIF files, with custom textures, then there is a small chance that the eyes will be invisible in-game. IF this happens, you can correct it with NifSkope.
*After converting the NIF files with SSE NIF Optimizer:
1: Start NifSkope.
2: Click the eyes and check all texture paths. Correct if incorrect, or change to any texture you want.
3: In the Block List view, expand the highlighted line (The line gets highlighted when selecting the eyes in the 3D window)
4: Select the NiAlphaPropert.
5: In the Block Detail view, change "Flags" to 4333 instead of whatever number there already is.
6: Save and close.

Repacking:
Go to the Conversion Data folder, which now contains all the converted files. Repack it into a zip/rar/7z package. This is your SSE mod.

That's it.

 

If you notice any problems caused by an SSE conversion from the SSEBP guide, please let me know: (LINK)