I too am having an install error. I know this is not were to post but was hoping it was a quick fix.
log
Aug 13 23:10:43 Media-Server.local installd[66237]: PackageKit: ----- Begin install -----
Aug 13 23:11:35 Media-Server.local installd[66237]: PackageKit: Install Failed: Error Domain=PKInstallErrorDomain Code=121 "An error occurred while updating system extension information." UserInfo=0x7fb0e1c07580 {NSUnderlyingError=0x7fb0e1c0bd90 "The operation couldn’t be completed. (kextcache error 71.)", NSLocalizedDescription=An error occurred while updating system extension information., arguments=(
"-update-volume",
"/",
"-Installer"
)} {
NSLocalizedDescription = "An error occurred while updating system extension information.";
NSUnderlyingError = "Error Domain=kextcache Code=71 \"The operation couldn\U2019t be completed. (kextcache error 71.)\"";
arguments = (
"-update-volume",
"/",
"-Installer"
);
}
Aug 13 23:11:36 Media-Server.local Installer[64620]: Install failed: The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance.
Aug 13 23:11:36 Media-Server.local Installer[64620]: Displaying 'Install Failed' UI.
Aug 13 23:11:36 Media-Server.local Installer[64620]: 'Install Failed' UI displayed message:'The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance.'.