In Texas, a beneficiary who accepts and retains benefits under a will may be estopped from contesting it. 564 2d 682. Some courts have held that the fact that the beneficiary did not have knowledge of all the facts on the need to contest the will at the time of his acceptance of benefits is immaterial. 620 2d 691. The same is true if the amount accepted is but a small part of what he would receive if the will was set aside. 935 2d 827. A good discussion of Texas cases dealing with the acceptance of benefits and standing to contest a will is in a case out of Fort Worth in 2016. No. 02-16-00103-CV.
Returning or tendering the property back to the estate may allow a person who accepted benefits to contest the will. Other courts have held that estoppel only applies if the contestant receives benefits that they would not have been entitled to under the will or intestacy. If you receive benefits that you would have received anyway, there is no estoppel. If you are in a situation where you believe that a will needs to be contested but you have accepted benefits, it is necessary that you consult with a Texas attorney who handles inheritance matters to see what your rights are.
On my blog, I have written about the acceptance of benefits and the enforcement of an arbitration clause in a will.
2019 Update: Even if a beneficiary accepts benefits under an estate, that does not stop him from pursuing other estate-related rights he has as a devisee, such as seeking to be named administrators. 06-18-00049-CV.