hPSCs were likely damaged while they were harvested. hPSCs may have been mechanically harvested by scraping or were pipetted too much or too vigorously. Lift Solution D1-treated hPSCs only by pipetting them up and down up to 15 times. The mixing of hPSCs with SeV may have also been done too strongly. Gently rock the plate several times to mix hPSCs with SeV.