Boot Camp Assistant is stuck at "Downloading windows support software...0 minutes 0 seconds remaining (for 48 hours and counting)" for Windows 10 Pro

No joy...switched to a Thunderbolt Ethernet, tried disabling System Integrity, and tried a few different Win10 ISOs. Console logs are below. There's some extra chatter from Safari but from multiple runs the deny system-fsctl are from BCA. Note that I get these even with SIC off. The 1st marker was roughly start of the assistant, the second marker after download and the end after the installing countdown where it gets to 0/0 remaining. That being said it looks like the ESD stuff installs successfully - so the hang seems right after.

lsof on BCA is uninteresting - /dev/null on stdin/out/err, a bunch of resource files, one KQUEUE and the usual domain socket for events.

3/18/16 3:22:25.744 PM mds[58]: (Volume.Normal:166) vsd:0x7ff697098200 DisabledStore recycle:2 context:{

DisabledRecycleCount = 2;

}

3/18/16 3:22:25.764 PM mds[58]: (Volume.Error:577) vsd:0x7ff695890800 Open failed. failureCount:2 {

DisabledRecycleCount = 2;

}

3/18/16 3:22:52.441 PM mds[58]: (Volume.Normal:166) vsd:0x7ff697045000 DisabledStore recycle:2 context:{

DisabledRecycleCount = 2;

}

3/18/16 3:22:52.460 PM mds[58]: (Volume.Error:577) vsd:0x7ff69704f000 Open failed. failureCount:2 {

DisabledRecycleCount = 2;

}

3/18/16 3:23:27.481 PM mds[58]: (Volume.Normal:166) vsd:0x7ff695890800 DisabledStore recycle:3 context:{

DisabledRecycleCount = 3;

}

3/18/16 3:23:27.500 PM mds[58]: (Volume.Error:577) vsd:0x7ff69704b000 Open failed. failureCount:3 {

DisabledRecycleCount = 3;

}

3/18/16 3:23:58.451 PM mds[58]: (Volume.Normal:166) vsd:0x7ff69704f000 DisabledStore recycle:3 context:{

DisabledRecycleCount = 3;

}

3/18/16 3:23:58.469 PM mds[58]: (Volume.Error:577) vsd:0x7ff694057400 Open failed. failureCount:3 {

DisabledRecycleCount = 3;

}

3/18/16 3:25:14.018 PM sandboxd[317]: ([242]) softwareupdated(242) deny system-fsctl 0x682f

3/18/16 3:25:19.937 PM Console[281]: Marker - Mar 18, 2016, 3:25:19 PM

3/18/16 3:25:27.500 PM mds[58]: (Volume.Normal:166) vsd:0x7ff69704b000 DisabledStore recycle:4 context:{

DisabledRecycleCount = 4;

}

3/18/16 3:25:27.520 PM mds[58]: (Volume.Error:577) vsd:0x7ff6940ba400 Open failed. failureCount:4 {

DisabledRecycleCount = 4;

}

3/18/16 3:25:31.512 PM com.apple.SecurityServer[75]: Session 100024 created

3/18/16 3:25:33.438 PM Safari[277]: ### Failed to load Addressbook class CNContactNameFormatter

3/18/16 3:25:39.128 PM Safari[277]: KeychainGetICDPStatus: keychain: -25300

3/18/16 3:25:39.128 PM Safari[277]: KeychainGetICDPStatus: status: off

3/18/16 3:25:39.187 PM Safari[277]: tcp_connection_tls_session_error_callback_imp 13 __tcp_connection_tls_session_callback_write_block_invoke.434 error 22

3/18/16 3:25:39.283 PM com.apple.xpc.launchd[1]: (com.apple.WebKit.Networking.36E7B90E-3919-4B83-A074-6B05A525006C[307]) Service exited with abnormal code: 1

3/18/16 3:25:39.286 PM syncdefaultsd[492]: accountsd has been removed from syncing apps.

3/18/16 3:25:58.849 PM mds[58]: (Volume.Normal:166) vsd:0x7ff694057400 DisabledStore recycle:4 context:{

DisabledRecycleCount = 4;

}

3/18/16 3:25:58.870 PM mds[58]: (Volume.Error:577) vsd:0x7ff695861000 Open failed. failureCount:4 {

DisabledRecycleCount = 4;

}

3/18/16 3:26:47.000 PM kernel[0]: process system_installd[490] thread 21728 caught burning CPU! It used more than 50% CPU (Actual recent usage: 99%) over 180 seconds. thread lifetime cpu usage 90.013772 seconds, (89.606314 user, 0.407458 system) ledger info: balance: 90005091566 credit: 90005091566 debit: 0 limit: 90000000000 (50%) period: 180000000000 time since last refill (ns): 90130300129

3/18/16 3:26:47.752 PM com.apple.xpc.launchd[1]: (com.apple.ReportCrash.Root[494]) Endpoint has been activated through legacy launch(3) APIs. Please switch to XPC or bootstrap_check_in(): com.apple.ReportCrash.DirectoryService

3/18/16 3:26:47.000 PM syslogd[40]: ASL Sender Statistics

3/18/16 3:26:49.131 PM spindump[455]: Saved cpu_resource.diag report for system_installd version ??? (???) to /Library/Logs/DiagnosticReports/system_installd_2016-03-18-152649_Marks-MacBook -Pro.cpu_resource.diag

3/18/16 3:27:39.804 PM UserEventAgent[271]: com.apple.TMHelperAgent.SetupOffer enabled

3/18/16 3:27:39.804 PM UserEventAgent[41]: Failed to send message because the port couldn't be created.

3/18/16 3:27:40.707 PM UserEventAgent[41]: Failed to send message because the port couldn't be created.

3/18/16 3:27:40.707 PM UserEventAgent[271]: com.apple.TMHelperAgent.SetupOffer enabled

3/18/16 3:27:41.218 PM sandboxd[317]: ([242]) softwareupdated(242) deny system-fsctl 0x682f

3/18/16 3:27:41.418 PM sandboxd[317]: ([242]) softwareupdated(242) deny system-fsctl 0x682f

3/18/16 3:27:57.077 PM Console[281]: Marker - Mar 18, 2016, 3:27:57 PM

Sorry, that was all nicely formatted in the reply compose window - the forums seem to strip all my line endings.

In the end I resolved my issue but none of the advice out there had anything to do with it...

At some point in the process I used the "diskutil verifyDisk /dev/disk0" and everything would verify but at the end it would report:

The volume could not be verified completely

File system check exit code is 8

Updating boot support partitions for the volume as required

Error: -69845: File system verify or repair failed

Underlying error: 8: POSIX reports: Exec format error

All attempts at repairDisk failed even in the recovery console. I tried the manual dd repair of the UEFI partition (no change) and deleting just the primary partition. But in the end I had to delete the MacOS primary volume all the way up to and including the VolumeGroup (as shown by "diskutil coreStorage list"). Unless I deleted all the way to that level "diskutil verifyDisk" reported the error.

After that "diskutil verifyDisk" would succeed. Then I reinstalled MacOS from scratch. Then finally Boot Camp Assistant was successful (other than I ran into the issue of the RealTek audio install hanging and having to do the manually install and kill the correct setup.exe instance).

So the lesson is BCA is dumb about even the slightest error in the disk, filesystems or partitions and provides no output (there was nothing in the console logs). Make sure a "diskutil verifyDisk" on your target disk is 100.0% error free (note that this error only showed up with the CLI command...the Disk Utility GUI would report "potential" problems with no details and then claim it fixed them). That fact this manifests itself as a silent hang kind of *****, but so it goes, Mac OS isn't very good at being transparent on errors.

So run "diskutil verifyDisk /dev/disk0" (device name could be different in some cases and will be different in the recovery mode console) and make sure it is 100.0% error free. If not resolve all issues there before any further attempts with Boot Camp.

In my case this was all a case of the Mac getting wrapped around the axle from the original issue when the Windows 8.1 upgraded added the boot system partition. I think this is optional in 8.0 and 8.1 home but now required in 8.1 Pro.

So I'm good...YMMV. Good luck.