Hey @Terra B Welch! So tell us everything you did. So you tried to make a preset but it failed, and then you were able to fix it? But when you did, it didn’t save all the mods in the preset?? (Also question: if you try making presets with fewer mods does it work? If so, it might be an issue with the size of the table we’re storing the presets into.... maybe there’s a limit...)

I've found an issue that makes all mods using V1 of the Workshop system (mods in the "...\common\Don't Starve Together\mods" folder, many of which weren't updated in a while) be ignored by the client presets.
I'm not sure if it's the same for servers, as I haven't tested that out.

Client mod presets and server presets have to be stored differently since they require different function calls. Is this what you’re refering to?

I should've been more especific.
What's happening to me is that every time I make a preset including, let's say, Boss Indicators (Last updated in 2017).

Whenever I disable all my mods and try to apply the preset again, all the other mods work just fine, except Boss Indicators. It is the only mod that doesn't become enabled with the preset.

Huh, we’ll look at it! Is it an old mod? Or do they update it frequently? And more importantly, does it have dependencies?

It was last updated September 2nd, 2017. It has no dependencies.

I have a similar problem. I'm a server mod preset. A dozen out of 65 mods can't be enabled via presets.

Hello!, I also seem to have an Issue where certain mods don't seem to be saving to the presets, here are the links to both mods.

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2868599299

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2955912123

I am not exactly sure what Is causing these not to save but most of my other mods seem to be saved to the presets besides these and a couple of others (Just showing these two as to not bombard you)

The game did not crash, so no error log was generated. However, I noticed that even after saving the mod preset, both client and server, not all mods remain saved, the same ones always have to be added manually.
I haven’t tested whether the mod still retains the individual mod settings even when they are not saved in the preset list.