Again about "<package> successfully unpacked and MD5 sums checked'' instead of installing

Hi all,
I use the latest RStudio and R on Windows 10.
I have successfully installed several packages, and then, after some updates, I met the problem that any install/update of a package just download it:

trying URL 'https://cran.rstudio.com/bin/windows/contrib/4.1/knitr_1.36.zip'
Content type 'application/zip' length 1469922 bytes (1.4 MB)
downloaded 1.4 MB

package ‘knitr’ successfully unpacked and MD5 sums checked

The downloaded binary packages are in
	C:\Users\dmitri\AppData\Local\Temp\Rtmp6BDmeK\downloaded_packages

No error is highlighted, just no installation.
The packages are supposed to install into "C:\R-Packages" (and there are a lot of packages there, so it worked). The environmental variable R_LIBS_USER is set to "C:\R-Packages". libPaths() returns

> .libPaths()
[1] "C:/R-Packages"                     
[2] "C:/Program Files/R/R-4.1.1/library"

I have set-up all permissions to the Library directory those I have only found in the Internet :-), I am the owner, I have explicit permission to write/read/execute.
The same happens if run RStudio as Administrator; if I run from the menu; if I specify lib="C:/R-Packages" in the RStudio console; if I run R from the command line without RStudio at all.
I am stuck...
Help me, please!

Kind regards,
Dmitri