A Motion to Vacate Sentence Under 28 U.S.C. 2255 is a legal document filed in federal court that allows a convicted criminal defendant to challenge his or her conviction or sentence on various legal grounds. This motion is often referred to as a 2255 Motion, and is available to any federal criminal defendant who believes his or her constitutional rights were violated during the course of his or her criminal case. The motion must be filed within a certain time period in order to be considered by the court. There are three main types of Motion to Vacate Sentence Under 28 U.S.C. 2255: 1. Actual Innocence Motion: A motion filed claiming that the defendant is actually innocent of the crime for which he or she was convicted. 2. Ineffective Assistance of Counsel Motion: A motion filed claiming that the defendant’s attorney provided ineffective assistance of counsel during the course of his or her criminal case. 3. Sentence Reduction Motion: A motion filed seeking a reduction of the defendant’s sentence due to a change in the law or other mitigating circumstances.