andresnorberto,
You still don't give us very much to work with in your question. First, notice Matthew's and my signature. This information can be very useful in answering questions as the answer can vary depending on hardware, OS, version of AC... Please add a similar signature to your posts. This is set up in the profile.
Next, since you are using a Mac have you tried the typical Mac fixes? If not, DO SO. This means checking your permissions. If they are wrong they could be the culprit. Next try dumping and rebuilding your preference file. Again this can cause this type of problem. If you have done these things already, then tell us that too.
There are some absolutely wonderful folk on this forum, and they can be very helpful if you give them the information they need to be able to help you.
Erich
AC 19 6006 & AC 20
Mac OS 10.11.5
15" Retina MacBook Pro 2.6
27" iMac Retina 5K