Unloading the package R6 2.2.0 in R 3.4.4 - r

Question

I am using R 3.4.4 in a very controlled environment in my company.
Basically I am having issues loading caret package:
Installation is successful with:
install.packages("caret", repos="http://cran.rstudio.com/", type= 'binary') - for windows
now when I try to load it, I get the below error:
library(caret)
Error: package or namespace load failed for ‘caret’ in loadNamespace(j <- i[[1L]], c(lib.loc, .libPaths()), versionCheck = vI[[j]]):
namespace ‘R6’ 2.2.0 is already loaded, but >= 2.2.2 is required
In addition: Warning message:
package ‘caret’ was built under R version 3.4.4
I have both R6 2.2.0 and R6 2.4.0 installed in my library. However, if I try to uninstall R6 2.2.0, I get the below error:
Error in value[[3L]](cond) :
Package ‘R6’ version 2.2.0 cannot be unloaded:
Error in unloadNamespace(package) : namespace ‘R6’ is imported by ‘mrsdeploy’, ‘CompatibilityAPI’ so cannot be unloaded
In addition: Warning message:
package ‘R6’ was built under R version 3.4.4
Help please. Thanks in advance.

Answer 1

Package dependencies are to blame: if the package cannot be unloaded because another package has imported some of its functions, then you need to first unload that package. In this case, the mrsdeploy and CompatibilityAPI packages should be removed first. Note that this might be recursive, since anything that has imported anything from either of those packages will need to be unloaded.
The suggestion was made to restart with a clean R session, and you said that it did not work. I suggest that you restarted R, but it was not a clean R session: if there is an .Rdata file or a project file that automatically loads the previous session's data and/or libraries, then a clean session starts ... pre-cluttered. In that case, you can work around it by starting R manually (perhaps not in RStudio or your preferred IDE) as R --no-restore, as that should not restore (well named!) the .Rdata file.