This might actually be an issue with your antivirus not having enough time to check the file before it is moved. Try telling R to pause for a minute when installing before moving the file over
run this code:
trace(utils:::unpackPkgZip, edit=TRUE)
Then go down to about line 140, you should see the following:
ret <- unlink(instPath, recursive = TRUE, force = TRUE)
if (ret == 0) {
Sys.sleep(0.5)
change the number in Sys.sleep from 0.5 to 2. For a huge package maybe do 3, but I've found almost everything works if you tell it to wait 2 seconds.
Note, this will reset the next time you restart your R session, so you will need to do it again.
Note - you still have to make sure you have access to write to the file where your packages are kept, but based on your post, it seems that you do. If you find out that you can't write to that directory, you can change where your r packages are kept - but that can be more annoying.