Thanks for your help. I did try, but it did not work. Same issue. I paste here the log:
Mar 24 18:27:13 MacBook-Air-di-Massimo-2 installd[387]: PackageKit: Adding client PKInstallDaemonClient pid=421, uid=503 (/System/Library/PrivateFrameworks/CommerceKit.framework/Versions/A/Resources/s toreassetd)
Mar 24 18:27:13 MacBook-Air-di-Massimo-2 storeassetd[421]: SUAppStoreUpdateController: authorize
Mar 24 18:27:13 MacBook-Air-di-Massimo-2 installd[387]: PackageKit: Adding client PKInstallDaemonClient pid=448, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
Mar 24 18:27:13 MacBook-Air-di-Massimo-2 softwareupdated[448]: Cannot find local product 031-53337 in index file
Mar 24 18:27:13 MacBook-Air-di-Massimo-2 installd[387]: PackageKit: Adding client PKInstallDaemonClient pid=448, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
Mar 24 18:27:13 MacBook-Air-di-Massimo-2 installd[387]: PackageKit: Removing client PKInstallDaemonClient pid=448, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
Mar 24 18:27:13 --- last message repeated 1 time ---
Mar 24 18:27:13 MacBook-Air-di-Massimo-2 storeassetd[421]: SUAppStoreUpdateController: disk space required for updates is: 2053596977
Mar 24 18:27:14 MacBook-Air-di-Massimo-2 softwareupdated[448]: Adding client SUUpdateServiceClient pid=421, uid=503, installAuth=NO rights=(), transactions=0 (/System/Library/PrivateFrameworks/CommerceKit.framework/Versions/A/Resources/s toreassetd)
Mar 24 18:27:14 MacBook-Air-di-Massimo-2 storeassetd[421]: SUAppStoreUpdateController: start install session with 031-53337
Mar 24 18:27:14 MacBook-Air-di-Massimo-2 softwareupdated[448]: SUUpdateSession startUpdateForProducts:<SUProduct: 031-53337> inForeground: YES staged: NO
Mar 24 18:27:14 MacBook-Air-di-Massimo-2 softwareupdated[448]: SoftwareUpdate: Added foreground transaction [0x1] for Command Line Tools (OS X 10.11) for Xcode-7.3
Mar 24 18:27:14 MacBook-Air-di-Massimo-2 softwareupdated[448]: SoftwareUpdate: starting download of 031-53337 (Command Line Tools (OS X 10.11) for Xcode-7.3)
Mar 24 18:27:14 MacBook-Air-di-Massimo-2 softwareupdated[448]: Cannot find local product 031-53337 in index file
Mar 24 18:27:20 MacBook-Air-di-Massimo-2 softwareupdated[448]: ContentLocator: No modified URL found
Mar 24 18:27:30 --- last message repeated 1 time ---
Mar 24 18:27:30 MacBook-Air-di-Massimo-2 softwareupdated[448]: Finished downloading package DevSDK_OSX1011.pkg to file:///var/folders/zz/zyxvpxvq6csfxvn_n00000s0000068/C/com.apple.SoftwareUpdat e/CFNetworkDownload_oICEeX.tmp (error (null)) from peer: 127.0.0.1
Mar 24 18:27:30 MacBook-Air-di-Massimo-2 suhelperd[449]: Verifying package at path: /Library/Updates/031-53337/DevSDK_OSX1011.pkg
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 softwareupdated[448]: Finished downloading package CLTools_Executables.pkg to file:///var/folders/zz/zyxvpxvq6csfxvn_n00000s0000068/C/com.apple.SoftwareUpdat e/CFNetworkDownload_7N9YTj.tmp (error (null)) from peer: 127.0.0.1
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 suhelperd[449]: Verifying package at path: /Library/Updates/031-53337/CLTools_Executables.pkg
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 softwareupdated[448]: No more tasks - invalidating session now
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 installd[387]: PackageKit: Adding client PKInstallDaemonClient pid=448, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 installd[387]: PackageKit: Removing client PKInstallDaemonClient pid=448, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: installd: Starting
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: installd: uid=0, euid=0
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: Adding client PKInstallDaemonClient pid=448, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 softwareupdated[448]: PackageKit: Enqueuing install with default quality of service (utility)
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: ----- Begin install -----
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: request=PKInstallRequest <2 packages, destination=/>
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: packages=(
"PKLeopardPackage <file:///Library/Updates/031-53337/CLTools_Executables.pkg>",
"PKLeopardPackage <file:///Library/Updates/031-53337/DevSDK_OSX1011.pkg>"
)
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: Will do receipt-based obsoleting for package identifier com.apple.pkg.CLTools_Executables (prefix path=/)
Mar 24 18:27:58 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: Will do receipt-based obsoleting for package identifier com.apple.pkg.DevSDK_OSX1011 (prefix path=/)
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: Install Failed: Error Domain=PKInstallErrorDomain Code=110 "Si è verificato un errore durante l'estrazione dei file dal pacchetto “CLTools_Executables.pkg.”" UserInfo={NSUnderlyingError=0x7f9b63007ef0 {Error Domain=PKXARArchiveErrorDomain Code=101 "archive verify failed" UserInfo={NSURL=file:///Library/Updates/031-53337/CLTools_Executables.pkg#Paylo ad, NSFileOwnerAccountID=0, NSFileHFSTypeCode=0, NSFileSystemFileNumber=15372209, NSFileExtensionHidden=false, NSFileSystemNumber=16777220, NSFileSize=141843861, NSFileGroupOwnerAccountID=0, NSFileOwnerAccountName=root, NSFilePosixPermissions=420, NSFileHFSCreatorCode=0, NSFileCreationDate=2016-03-24 17:27:20 +0000, NSFileType=NSFileTypeRegular, NSFileGroupOwnerAccountName=wheel, NSFileReferenceCount=1, NSFileModificationDate=2016-03-24 17:27:58 +0000, NSLocalizedDescription=archive verify failed}}, NSFilePath=/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/C/PKInstallSandboxMan ager-SystemSoftware/22D184E2-6AFA-472C-AEE6-4C835712748F.activeSandbox/Root, NSURL=file:///Library/Updates/031-53337/CLTools_Executables.pkg, PKInstallPackageIdentifier=com.apple.pkg.CLTools_Executables, NSLocalizedDescription=Si è verificato un errore durante l'estrazione dei file dal pacchetto “CLTools_Executables.pkg.”} {
NSFilePath = "/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/C/PKInstallSandboxManager-Syste mSoftware/22D184E2-6AFA-472C-AEE6-4C835712748F.activeSandbox/Root";
NSLocalizedDescription = "Si \U00e8 verificato un errore durante l'estrazione dei file dal pacchetto \U201cCLTools_Executables.pkg.\U201d";
NSURL = "file:///Library/Updates/031-53337/CLTools_Executables.pkg";
NSUnderlyingError = "Error Domain=PKXARArchiveErrorDomain Code=101 \"archive verify failed\" UserInfo={NSURL=file:///Library/Updates/031-53337/CLTools_Executables.pkg#Paylo ad, NSFileOwnerAccountID=0, NSFileHFSTypeCode=0, NSFileSystemFileNumber=15372209, NSFileExtensionHidden=false, NSFileSystemNumber=16777220, NSFileSize=141843861, NSFileGroupOwnerAccountID=0, NSFileOwnerAccountName=root, NSFilePosixPermissions=420, NSFileHFSCreatorCode=0, NSFileCreationDate=2016-03-24 17:27:20 +0000, NSFileType=NSFileTypeRegular, NSFileGroupOwnerAccountName=wheel, NSFileReferenceCount=1, NSFileModificationDate=2016-03-24 17:27:58 +0000, NSLocalizedDescription=archive verify failed}";
PKInstallPackageIdentifier = "com.apple.pkg.CLTools_Executables";
}
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: Running idle tasks
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: Removing client PKInstallDaemonClient pid=448, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 system_installd[579]: PackageKit: Done with sandbox removals
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 softwareupdated[448]: SoftwareUpdate: extraction error on install of 031-53337 (reset to download error state to allow retry): Error Domain=SUErrorDomain Code=311 "Impossibile verificare “Command Line Tools (OS X 10.11) for Xcode”." UserInfo={SUErrorUpdateTitle=Command Line Tools (OS X 10.11) for Xcode, SUErrorUpdateProductKey=031-53337, NSLocalizedDescription=Impossibile verificare “Command Line Tools (OS X 10.11) for Xcode”.}
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 softwareupdated[448]: Removing 031-53337
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 softwareupdated[448]: Removed local product for 031-53337 (1)
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 softwareupdated[448]: Stopping transaction with ID [0x1]
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 softwareupdated[448]: SoftwareUpdate: Removed foreground transaction [0x1]
Mar 24 18:27:59 MacBook-Air-di-Massimo-2 storeassetd[421]: SUAppStoreUpdateController: status for 031-53337: 031-53337 (a=0x3): download error (0 of 180562737) 1.0% -1.0s (error: Error Domain=SUErrorDomain Code=311 "Impossibile verificare “Command Line Tools (OS X 10.11) for Xcode”." UserInfo={SUErrorUpdateTitle=Command Line Tools (OS X 10.11) for Xcode, SUErrorUpdateProductKey=031-53337, NSLocalizedDescription=Impossibile verificare “Command Line Tools (OS X 10.11) for Xcode”.})
Mar 24 18:28:00 MacBook-Air-di-Massimo-2 softwareupdated[448]: Running session-idle tasks.
Mar 24 18:28:00 MacBook-Air-di-Massimo-2 softwareupdated[448]: Checking for inapplicable local products remaining on disk for cleanup