While trying to update my Android SDK I am encountering this error when trying to install this particular package:
The error message was Failed to rename directory C:\devtools\android-sdk\system-images\android-21\google_apis\x86 to C:\devtools\android-sdk\temp\SystemImagePackage.old01. I deleted the C:\devtools\android-sdk\temp\SystemImagePackage.old01 directory by hand (it was a leftover? I don't know) and it was able to proceed.