My sister was named executor and three of us are beneficiaries before the will was filed She changed the locks and would not let me on the property was this legal?

In order to obtain the authority of an executor your sister must file the will for probate. The court will review the will and if it is allowed then your sister will be appointed the executor if no one objects. She is not the executor until she has been appointed by the court. You will be notified. Until she has been appointed by the court she has no power whatsoever. However, perhaps she is preserving the estate until the estate is settled, preventing heirs from removing any property. If that is the case then she is acting responsibly.

Remember that once they are appointed, the executor has the power and authority to take charge of all the assets and settle the estate under the supervision of the probate court and according to the provisions in the will. She should not be secretive during that process. Once the will is filed for probate the file becomes a public record and anyone can review it. You can go to the probate court, request the file and monitor the executor's progress in the settling of the estate by reading through all the documents contained in the file.