[r] R not finding package even after package installation

I have always worked with the zoo package, that I have installed a long time ago. Today, I created a new R script, and ran library(zoo) and got the following error:

 > library(zoo)
 Error in library(zoo) : there is no package called ‘zoo’

Odd.. Still, I tried reinstalling the package using install.packages("zoo"), and get the following:

 > install.packages("zoo")
 Installing package(s) into ‘C:/Users/U122337.BOSTONADVISORS/Documents/R/win-library/2.15’
 (as ‘lib’ is unspecified)
 --- Please select a CRAN mirror for use in this session ---
 trying URL 'http://cran.cnr.Berkeley.edu/bin/windows/contrib/2.15/zoo_1.7-10.zip'
 Content type 'application/zip' length 874474 bytes (853 Kb)
 opened URL
 downloaded 853 Kb

 package ‘zoo’ successfully unpacked and MD5 sums checked
 Warning: cannot remove prior installation of package ‘zoo’

The downloaded binary packages are in
    C:\Users\U122337.BOSTONADVISORS\AppData\Local\Temp\Rtmp404t8Y\downloaded_packages

When I try uploading the package, I get the error again that the zoo package doesn't exist.

I have no idea what's happening. I exited the GUI and restarted it, same problem. I have always worked with this package, and I have no idea why this is happening now.

So the package will be downloaded in a temp folder C:\Users\U122337.BOSTONADVISORS\AppData\Local\Temp\Rtmp404t8Y\downloaded_packages from where it will be installed into your library folder, e.g. C:\R\library\zoo

What you have to do once install command is done: Open Packages menu -> Load package...

You will see your package on the list. You can automate this: How to load packages in R automatically?

I had this problem and the issue was that I had the package loaded in another R instance. Simply closing all R instances and installing on a fresh instance allowed for the package to be installed.

Generally, you can also install if every remaining instance has never loaded the package as well (even if it installed an old version).

When you run

install.packages("whatever")

you got message that your binaries are downloaded into temporary location (e.g. The downloaded binary packages are in C:\Users\User_name\AppData\Local\Temp\RtmpC6Y8Yv\downloaded_packages ). Go there. Take binaries (zip file). Copy paste into location which you get from running the code:

.libPaths()

If libPaths shows 2 locations, then paste into second one. Load library:

library(whatever)

Fixed.