2. Dismissal because the People cannot prove their case beyond a reasonable doubt. (usually involves a missing, recaltrant or reluctant witness)
2. Acquittal at trial. (requires good defense facts)
2. Dismissal by facial insufficiency. (requires a poorly drafted complaint)
5. Dismissal in the interests of justice. (requires compelling circumstances)
Any of the above will result in a permanently sealed record.
Sealing under 160.55 requires that the matter be reduced from a crime (misdemeanor or felony) to a violation (usually a 240.20).
Sealing under 160.50 requires a dismissal and, in my experience, the most likely means of securing a dismissal are as follows:
1. Adjournment in contemplation of dismissal ("ACD") (requires no prior record or a minimal prior record)
2. Violation of Speedy trial under New York CPL 30.30. (requires various conditions and 90 days of time when the prosecutor is not ready for trial on a misdemeanor and 180 when they are not ready on a felony))