Update loop with "Command Line Tools (OS X 10.10) for Xcode 7.0"

Help, I'm stuck unable to update "Command Line Tools (OS X 10.10) for Xcode 7.0"!

I'm experiencing a dreaded "update loop" where the same update fails but gets added to the update history repeatedly. In my case, the update is "Command Line Tools (OS X 10.10) for Xcode 7.0". First I tried quitting everything, restarting, and doing update again to no avail. Then made some other attempts:

I've tried deleting `zz` and restarting as described here: Re: encountering severe problems trying to get the os X update to install properly. The update page is showing it insta…

I've tried the three-step fix described here: http://apple.stackexchange.com/questions/206087/how-do-i-fix-a-broken-os-x-updat e-that-shows-as-both-available-and-insta…

Nothing has worked yet.

Some details about my Mac:

MacBook Pro (Retina, 13-inch, Early 2015)

Model Identifier: MacBookPro12,1

System Version: OS X 10.10.5 (14F27)

Kernel Version: Darwin 14.5.0

Here's a `/var/log/install.log` dump of what's happening in my case:

Marker - Sep 18, 2015, 3:37:23 PM

Sep 18 15:37:32 LYNAUGH installd[637]: PackageKit: Adding client PKInstallDaemonClient pid=272, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)

Sep 18 15:37:32 LYNAUGH installd[637]: PackageKit: Removing client PKInstallDaemonClient pid=272, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)

Sep 18 15:37:32 LYNAUGH storeassetd[511]: SUAppStoreUpdateController: disk space required for updates is: 1983419680

Sep 18 15:37:34 LYNAUGH storeassetd[511]: SUAppStoreUpdateController: start install session with 031-10481

Sep 18 15:37:34 LYNAUGH softwareupdated[272]: SoftwareUpdate: Added foreground transaction [0x4] for Command Line Tools (OS X 10.10) for Xcode-7.0

Sep 18 15:37:34 LYNAUGH softwareupdated[272]: SoftwareUpdate: starting download of 031-10481 (Command Line Tools (OS X 10.10) for Xcode-7.0)

Sep 18 15:37:34 LYNAUGH softwareupdated[272]: ContentLocator: Modified URL is: http://192.168.10.62:49789/content/downloads/44/09/031-10481/jevfmj4fnqatxdq63tn q9q1h1w8121067f/CLTools_Executables.pkg?source=swcdn.apple.com

Sep 18 15:37:34 LYNAUGH softwareupdated[272]: ContentLocator: Modified URL is: http://192.168.10.62:49789/content/downloads/44/09/031-10481/jevfmj4fnqatxdq63tn q9q1h1w8121067f/DevSDK_OSX1010.pkg?source=swcdn.apple.com

Sep 18 15:37:42 LYNAUGH softwareupdated[272]: Finished downloading package DevSDK_OSX1010.pkg to file:///var/folders/zz/zyxvpxvq6csfxvn_n00000s0000068/C/com.apple.SoftwareUpdat e/CFNetworkDownload_AEzVDm.tmp (error (null))

Sep 18 15:37:42 LYNAUGH suhelperd[279]: Verifying package at path: /Library/Updates/031-10481/DevSDK_OSX1010.pkg

Sep 18 15:37:56 LYNAUGH softwareupdated[272]: Finished downloading package CLTools_Executables.pkg to file:///var/folders/zz/zyxvpxvq6csfxvn_n00000s0000068/C/com.apple.SoftwareUpdat e/CFNetworkDownload_gBhyia.tmp (error (null))

Sep 18 15:37:56 LYNAUGH suhelperd[279]: Verifying package at path: /Library/Updates/031-10481/CLTools_Executables.pkg

Sep 18 15:37:56 LYNAUGH softwareupdated[272]: No more tasks - invalidating session now

Sep 18 15:37:56 LYNAUGH softwareupdated[272]: SoftwareUpdate: finished download of 031-10481

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: Adding client PKInstallDaemonClient pid=272, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: Removing client PKInstallDaemonClient pid=272, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: Adding client PKInstallDaemonClient pid=272, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)

Sep 18 15:37:56 LYNAUGH softwareupdated[272]: PackageKit: Enqueuing install with default quality of service (utility)

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: ----- Begin install -----

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: request=PKInstallRequest <2 packages, destination=/>

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: packages=(

"PKLeopardPackage <file:///Library/Updates/031-10481/CLTools_Executables.pkg>",

"PKLeopardPackage <file:///Library/Updates/031-10481/DevSDK_OSX1010.pkg>"

)

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: Will do receipt-based obsoleting for package identifier com.apple.pkg.CLTools_Executables (prefix path=/)

Sep 18 15:37:56 LYNAUGH installd[637]: PackageKit: Will do receipt-based obsoleting for package identifier com.apple.pkg.DevSDK_OSX1010 (prefix path=/)

Sep 18 15:37:57 LYNAUGH installd[637]: PackageKit: Install Failed: Error Domain=PKInstallErrorDomain Code=110 "An error occurred while extracting files from the package “CLTools_Executables.pkg”." UserInfo=0x7f9a685369b0 {NSUnderlyingError=0x7f9a68507be0 "archive verify failed", NSURL=file:///Library/Updates/031-10481/CLTools_Executables.pkg, PKInstallPackageIdentifier=com.apple.pkg.CLTools_Executables, NSLocalizedDescription=An error occurred while extracting files from the package “CLTools_Executables.pkg”.} {

NSLocalizedDescription = "An error occurred while extracting files from the package \U201cCLTools_Executables.pkg\U201d.";

NSURL = "file:///Library/Updates/031-10481/CLTools_Executables.pkg";

NSUnderlyingError = "Error Domain=PKXARArchiveErrorDomain Code=101 \"archive verify failed\" UserInfo=0x7f9a685cdac0 {NSURL=file:///Library/Updates/031-10481/CLTools_Executables.pkg#Scripts, NSFileOwnerAccountID=0, NSFileHFSTypeCode=0, NSFileSystemFileNumber=23757579, NSFileExtensionHidden=false, NSFileSystemNumber=16777220, NSFileSize=125545871, NSFileGroupOwnerAccountID=0, NSFileOwnerAccountName=root, NSFilePosixPermissions=420, NSFileHFSCreatorCode=0, NSFileCreationDate=2015-09-18 22:37:34 +0000, NSFileType=NSFileTypeRegular, NSFileGroupOwnerAccountName=wheel, NSFileReferenceCount=1, NSFileModificationDate=2015-09-18 22:37:56 +0000, NSLocalizedDescription=archive verify failed}";

PKInstallPackageIdentifier = "com.apple.pkg.CLTools_Executables";

}

Sep 18 15:37:57 LYNAUGH installd[637]: PackageKit: Running idle tasks

Sep 18 15:37:57 LYNAUGH installd[637]: PackageKit: Done with sandbox removals

Sep 18 15:37:57 LYNAUGH installd[637]: PackageKit: Removing client PKInstallDaemonClient pid=272, uid=200 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)

Any help would be greatly appreciated.