This article provides a critical analysis of a problematic aspect of modern criminal procedure: the procedure for eliminating "doubts and ambiguities" that arise during the execution of a sentence (Clause 15, Article 397 of the Criminal Procedure Code of the Russian Federation). The author notes a systemic crisis in the regulation of this area, caused by the fundamental ambiguity of the key concepts of "doubts and ambiguities" and "the essence of the sentence," which lack a legal definition. It is emphasized that the current model list in Resolution No. 21 of the Plenum of the Supreme Court of the Russian Federation dated December 20, 2011, inheriting the flaws of its Soviet predecessor, is open-ended, granting courts unlimited discretionary powers. This leads to the substitution of appellate review for a simplified procedure for "correcting" a sentence, which violates the principles of legal certainty and adversarial proceedings. As a priority measure to overcome the lack of legal regulation, the author proposes establishing in the Russian Criminal Procedure Code an exhaustive (closed) list of grounds for eliminating deficiencies; a clear legal distinction between technical errors and material mistakes, correctable only through review; abandoning the misleading terminology of "clarification" in favor of the precise concepts of "error correction" and "elimination of ambiguities," and so on.