Generating errors followed by corrective feedback enhances retention more effectively than does reading—the benefit of errorful generation—but people tend to be unaware of this benefit. The current research explored this metacognitive unawareness, its effect on self-regulated learning, and how to alleviate or reverse it. People’s beliefs about the relative learning efficacy of generating errors followed by corrective feedback compared to reading, and the effects of generation fluency, are also explored. In Experiments 1 and 2, lower judgments of learning (JOLs) were consistently given to incorrectly generated word pairs than to studied (read) pairs and led participants to distribute more study resources to incorrectly generated pairs, even though superior recall of these pairs was exhibited in the final test. In Experiment 3, a survey revealed that people believe that generating errors followed by corrective feedback is inferior to reading. Experiment 4 was designed to alter participants’ metacognition by informing them of the errorful generation benefit prior to study. Although metacognitive misalignment was partly countered, participants still tended to be unaware of this benefit when making item-by-item JOLs. In Experiment 5, in a delayed JOL condition, higher JOLs were given to incorrectly generated pairs and read pairs were more likely to be selected for restudy. The current research reveals that people tend to underestimate the learning efficiency of generating errors followed by corrective feedback relative to reading when making immediate item-by-item JOLs. Informing people of the errorful generation benefit prior to study and asking them to make delayed JOLs are effective ways to alleviate this metacognitive miscalibration.