So what should I do now ? Redownload the IDE ?
Instead of telling us whether or not that directory really is your sketch directory? I can't see how downloading the IDE again will be a satisfactory alternative.
If that IS your sketch directory, downloading the IDE again will leave it exactly the same, so your problem won't have gone away. Again, I don't see downloading the IDE again as a useful thing to do.
If that IS your sketch directory, deleting the SoftwareSerial folder WILL solve your problem.
But, it's your decision as to what to do.