Change of location of R libraries throws error - r

Question

I have an issue with the library path of R. Maybe the answer is out there already, but I was not able to find it. I am using R together with RStudio Version 1.1.456. All my additional libraries used to be in a directory dir1 <- \\SHARE\TOOLS_OLD$\R-3.5.1 which I append with .libPaths(dir1). In this setup, everything works as expected.
The problem occured after I copied all the libraries in directory \\SHARE\TOOLS_OLD$\R-3.5.1 to a new location \\NAS\TOOLSNEW$\R-3.5.1. I did not update the R version and I want to keep all the package versions the same such that I have exactly the same setup as before. That is why I did not reinstall the packages in the new location.
When I open a new R session and run the three lines of code
dir2 <- \\NAS\TOOLSNEW$\R-3.5.1
.libPaths(dir2)
.libPaths()
I get the correct output of .libPaths()
[1] "\\\\NAS/TOOLSNEW$/R-3.5.1" "C:/Apps/R-3.5.1/library"
but R also throws an error:
Error: invalid version specification ‘NA’
In addition: Warning message:
In utils:::packageDescription(packageName, fields = "Version") :
no package 'knitr' was found
Apparently some packages remember the original location where they were installed. Is there a way to copy packages to a new location without reinstalling them? If that is not possible, is there an easy (i.e. non-manual) way to reinstall my package tree without upgrading any of the packages (including the dependencies) i.e. defining the version of each package?
Thanks for your help!
PS: Here is my session info, just in case.
R version 3.5.1 (2018-07-02)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)
Matrix products: default
locale:
[1] LC_COLLATE=German_Switzerland.1252 LC_CTYPE=German_Switzerland.1252
LC_MONETARY=German_Switzerland.1252 LC_NUMERIC=C
[5] LC_TIME=German_Switzerland.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] compiler_3.5.1 tools_3.5.1 yaml_2.2.0

Answer 1

The problem can have many causes, e.g. there might be some dependencies which are lost by copying the package folder or that the registry entries don't match anymore, but I'm guessing here. When you copy packages from older versions you have to run update.packages (but this might update any package to the currently available version, which you don't want). Check out the R-FAQ and this Stackoverflow question.
You can install packages of a certain version with the devtools package.
install.packages("devtools")
require(devtools)
install_version(somePackage, version = neededVersion)
How I did it was I created a data.frame of all the required packages with the corresponding version number, like
> requiredPkgs
Package Version
condformat "condformat" "0.9.0"
DT "DT" "0.17"
formattable "formattable" "0.2.1"
ggplot2 "ggplot2" "3.3.3"
ggthemes "ggthemes" "4.2.4"
htmlTable "htmlTable" "2.1.0"
and then installed them in a loop
for(iPkg in requiredPkgs) {
install_version(iPkg[1], version = iPkg[2]
}