If you're thawing the shredded cheese at room temperature it can take around 1 hour to 2 hours for the shredded cheese to fully thaw out.
Usually though 30 minutes is enough time to thaw the frozen shredded cheese out to use it in baking foods or melting on things.
But to eat the shredded cheese such as on salads etc without melting it can take around 1 hour to 2 hours depending on the room temperature to thaw the shredded cheese out.
You can place the shredded cheese in the microwave for 10 to 20 seconds which should thaw it out enough to use.