How can I stop Skyrim from downloading mods I'm no longer subscribed to?

Every time I open Skyrim the launcher downloads mods that I previously subscribed to and gives me a message that says, "Synchronization complete. Some mods that were unsubcribed were subscribed to and loaded".

For all of these mods, I have (a) checked that I'm not subscribed to that mod on the Steam Workshop and (b) checked I don't have the mod file in my skyrim data folder. I can delete everything in the Data Files tab, unsubcribe from everything at the same time, go to the website and check I am subscribed to nothing, and the next time I open Skyrim it redownloads all the mods I don't want.

The best way to solve your problem is to unsubscribe from the Mods. In this way, Skyrim Launcher will no longer download them automatically.

To unsubscribe them, you needs to go to 'Data Files' on your launcher, then click on Skyrim Workshop and login to the Workshop.

From there, you should see your display pic at the right hand bar. Click on that, then click on Subscribed Items. You will see all the mods that your're subscribed to. Unsubscribe from those that you don't want any more.

You were unable to get rid of them previously from the 'Data Files' tab because all the mods are linked to your account. You have to manually remove them from the Skyrim Workshop.

I hope this helps! :)