Absolutely! Ever keep brick of cream cheese in fridge too long & go to use it & it is moldy,black ugh Well then you mix cr. cheese, milk , butter& powdered sugar & you have a regular mold factory if you don't refrigerate. If I make a 9x13 cake I can usually squeeze it in on top of milk & juices, if you have bunch of kids they'll have it on the floor getting the milk out. It does freeze well, cut your cake up & freeze it in small portions & take out just what you want & be safe. Some food poisoning is very nasty. Don't chance it!I've known people that went to wedding & 50 were in hospital. In that case it was a salad dressing not cold enough at a fancy hilltop buffet place also had another party that night & 200 more got sick, health dept numbered them. Some were in hospital for a week. Not something to fool around with!!We want you on the forums!!! LOL But this is serious-don"t do it! Jan

Wow, I'm so glad I refrigerated that cake. I had never made any kind of frosting before, but common sense told me that cream cheese probably should be kept cold. I love cream cheese frosting...the homemade kind, but the stuff you buy in the cans is not so impressive. Thanks so much for your reply sunny.
Dee in michigan

A cake frosted with a cream cheese frosting will keep perfectly well for 2 or 3 days at room temperature.
The frosting will get soft, but won't mold in that short a period.
sugar is a mold deterrant. Ever see moldy fudge? it has butter and milk in it.
Linda C

That would depend on the climate.

I have also kept mine out until the cake was gone with no problems (3-4 days). I wouldn't leave the block of cream cheese out, but have never had a problem with a cake. I don't want to eat cold cake, and I couldn't exactly microwave a slice of cake.