Had this issue couple years ago after installing a widget and couldn't figure it out so i wiped my game and started over. Yesterday had it again this time though I know that the issue was from having over 500 esps and files of the like in my data folder. Tested it by decressing and increasing to make sure over and over. Note that only 253 were active ever but i just had some mods i used as resources in the creation kit sitting there for when I needed them. So check how many esps and other files you have in that directory with something like Wyre Bash (Which will yell at you :) and save yourself some irritation. Hopefully this solves it for some.