For anybody who comes to this old post via a search: the Internet is full of lists of things to try if an app fails to install. What is missing is the standard troubleshooting approach: what is the reason for the failure?

This is just a one-off anecdote, I don't know how general it is. I was having repeated failure for an update for one particular app from the Play Store. I downloaded the .apk and used the Total Commander file manager to try to install it. It failed, but with a very specific error message. (In my case the update required a permission which clashed with another app; the only thing I could do was notify the app's owner and hope that the clash could be resolved, anything else would be a waste of time.)

While not directly answering the question "what are the common reasons", this, if it works more generally, is a way to find the actual reason for a failure without having to make troublesome random tests doomed to failure.