Sparrow for Mac resets after quitting
Sparrow's development was halted quite a while ago, and as OS X has developed, Sparrow hasn't kept up.

Most notably is the addition of Containers for app's data and I speculate that this is causing some problem with some code in Sparrow. Obviously, this is speculation as I haven't seen Sparrow's source code, but I don't think it's something that you can fix yourself—it's most probably a bug in Sparrow's code.