error after installing ggmap in r

Question

I installed package ggmap. But when I wanted to use it , I got following error:

library(ggmap)
loading required package ggplot2
Error in readRDS(nsINFoFilePath) : unknown input format
Error: package or namespace load failed for 'ggmap'

I also uninstalled it using utils and reinstalled but same error appears again.

Answer 1

Try uninstalling ggplot2 first:

uninstall.packages("ggplot2")

and then installing both ggplot2 and ggmap.