I have Steam installed on my E drive. I changed my Vortex mods folder in Vortex's settings to my E drive as well. But I have the error popup that says "Mods can't be deployed" because, as the popup says, my mods staging folder needs to be on the same disk as my game.
Here's how I have it:
E:/Steam/steamapps/.../Fallout 4
and then
E:/Vortex/fallout4
I've also tried starting Vortex as an administrator, and it didn't fix it.
All the other "solutions" that the error message gives are useless and say they "can't solve".
What's going on?