RSelenium: server signals port is already in use

The process is composed of two parts a server (the Selenium Server) and a client(the browser you initiate). The close method of the remoteDriver class closes the client (the browser). The server also needs to be stopped when you are finished.

To stop the server when you are finished:

library(RSelenium)rD <- rsDriver(verbose = FALSE,port=4444L)remDr <- rD$clientremDr$close()

Now either explicitly stop the server:

rD$server$stop()

or if the rD object is removed the server will be stopped upon garbage collection:

library(RSelenium)rD <- rsDriver(verbose = FALSE,port=4444L)remDr <- rD$clientremDr$close()rm(rD)gc()

I did not have issues until recently. What worked for me is to use the solution above and as per the solution in this thread to add a line to kill the Java instance(s) inside RStudio.

remDr$close()rD$server$stop()rm(rD, remDr)gc()system("taskkill /im java.exe /f", intern=FALSE, ignore.stdout=FALSE)

The command:

system("taskkill /im java.exe /f", intern=FALSE, ignore.stdout=FALSE)

will free all the ports.

If you want to free a particular port, you can do this:

#get the PID of the process you launched

pid <- driver$server$process$get_pid()

#pasting this PID in the following command (will kill all the child processes as well, closes the browser as well)

system(paste0("Taskkill /F /T" ," /PID ", pid))