The Rochester City School District says it had found "no viable threat" from talk about a wildcat strike on Friday.
A new activist group is calling for a walkout by district staff to protest layoffs in the district and demand more state aid.
Friday is a half-day for students.
The district has advised principals against approving paid sick days Friday without a doctor's note.
And the unions -- including the Rochester Teachers Association -- are reminding members that they could lose two days' pay for a one-day walkout.