Error during installation of ggbiplot

[Jacktpk]

I have followed the instructions:

library(devtools)
install_github("vqv/ggbiplot")

and I have this error

Error: Failed to install 'ggbiplot' from GitHub:
(converted from warning) cannot remove prior installation of package ‘testthat’

Can someone help me please?

[burch-cm]

I was also getting the same error on attempted install with {devtools}. The error message mentioned a DLL it couldn't find, and I manually installed that package ( with install.packages() ). I had to install {fansi}, {utf8}, {Rcpp}, and {plyr}. After that, it finally installed for me.