Steps:
1.- Create the destination directory in the desired drive with space, a lot of GB space
2.- Then copy all the content from %USERPROFILE%\AppData\Roaming\Unity into this new directory
3.- Delete the entire directory %USERPROFILE%\AppData\Roaming\Unity
4.- As and admin execute the command prompt and type:
mklink /D "%USERPROFILE%\AppData\Roaming\Unity" "D:\Unity Assets\"
Note Replace *D:\Unity Assets* with the name of your directory