Downgrading (user homes) to macOS Sierra

Question

Because of having issues with High Sierra, I had to downgrade to Sierra. My macOS is on an internal SSD (of my Mac Pro) and my user homes are on an external SSD. When downgrading using a backup, Time Machine only replaced macOS (on the internal SSD), but not the user homes (on the external SSD).

Looks like Sierra is not happy with my High Sierra user homes:

• Messages hangs

• identityservicesd and callservicesd are constantly crashing

• my screen turns black, sometimes every few seconds. possibly having to do with the crashes.

Essentially the same problems like in this thread (which is locked): https://discussions.apple.com/thread/8105075

The user of the post above said he could solve his issues with a reinstall of Sierra (which I cannot do and I am also not convinced this changes anything) plus “restoring files by hand from my time machine backup drive with rsync and other command-line tools”. Any idea how to do this or which files need replacement? Deleting ~/Library/Caches did not help. I also restored these with Time Machine which also did not help:

• ~/Library/Messages
• ~/Library/Preferences/com.apple.identityservicesd.plist
• ~/Library/Preferences/com.apple.TelephonyUtilities.plist

Any other idea?

Some detail on the crashes:

Process:               identityservicesd [803]
Path:                  /System/Library/PrivateFrameworks/IDS.framework/identityservicesd.app/Contents/MacOS/identityservicesd
Identifier:            identityservicesd
Version:               10.0 (1000)
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           identityservicesd [803]
User ID:               501

Date/Time:             2018-02-01 10:00:56.010 +0100
OS Version:            Mac OS X 10.12.6 (16G1212)
Report Version:        12
Anonymous UUID:        F9C97F8F-70BD-CA59-5E14-105C64D05D82


Time Awake Since Boot: 57 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Application Specific Information:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFData count]: unrecognized selector sent to instance 0x7fa61a012200'
terminating with uncaught exception of type NSException
abort() called

and

Process:               callservicesd [996]
Path:                  /System/Library/PrivateFrameworks/TelephonyUtilities.framework/callservicesd
Identifier:            callservicesd
Version:               1.0 (1.0)
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           callservicesd [996]
User ID:               501

Date/Time:             2018-02-01 10:09:25.222 +0100
OS Version:            Mac OS X 10.12.6 (16G1212)
Report Version:        12
Anonymous UUID:        F9C97F8F-70BD-CA59-5E14-105C64D05D82


Time Awake Since Boot: 560 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Application Specific Information:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFData count]: unrecognized selector sent to instance 0x7fd24b86e800'
terminating with uncaught exception of type NSException
abort() called

Update: Trying to restore ~/Library/Preferences completely with Time Machine essentially resulted in a deletion. Now the problems are gone but my preferences are also gone. Luckily I have copied the folder before doing so. Thus if I knew which of the preferences needed replacement by the Sierra ones I could restore the rest by hand. Any idea?

Answer 1

It will be very difficult to isolate the issue to individual preference files, since there could be several subtle issues.

Better to take the opposite approach - start with no preferences and only copy the old preferences over one by one as you come across them. That is, as you discover that you have a preference that needs updating, find the single preference file that will give you that preference, and restore it. Re-test and only proceed if things are still stable. Will be a drawn out process, but necessarily so I think. When you can no longer add individual preferences, consider the restoration finished and many set the remaining preferences.

This complex relationship between the OS, Applications and user files is why Apple created Migration Assistant. It might not be help here but it is useful to know just how intricate the process is of "migrating" from one OS version to another.

Answer 2

I am going to go out on limb and say that Apple never intended users to downgrade an OS in place like you’re attempting. You’re basically being your own test pilot which could be seen as either very brave or very foolish. I would suggest that what you’re attempting is not only more trouble than it’s worth, you may never get the results you desire. That’s because even if you could resolve this particular problem it’s more than likely you’re going to encounter something else that blows up in your face eventually. Similarly as others have suggested, assuming you have alternate storage, copy your files and your Library directory from your homedir and start with a clean install of Sierra. Reinstall your apps, use time machine to snapshot the system, and then attempt to restore various settings by manually copying the respective plist files for apps that the you are confident are reverse compatible and making new backups of your system up along the way. If you wind up hosing things with your manual recombobulation of your system, just restore to the last known good state and try try again. If you cannot get the system stable enough to copy your files, use a bootable thumb drive like an installer which can be built following one of the many guides on creating installation thumb drives. Once booted, open a terminal window, attach the external storage, mounted it, and rsync your files. Probably not what you were hoping for, but I think cutting your losses and not succumbing to the sunk-cost fallacy will end up saving you time. Good luck!

Answer 3

I had exactly the same issue (including downgrading from high sierra). I took a slightly different approach to the OP and took all files containing the word "apple" in my Preferences directory and stored them in a separate directory "Maybe_Bad". I then went to my last Sierra backup (which sadly was all the way back in August 2017 because I'm on the beta program for OS X) and copied across all the apple files in that backup's Preferences directory. Also, I copied across the old ~library/Messages folder because High Sierra uses a different database for Messages than Sierra (and because of that by the time we're done you'll have lost all messages while in High Sierra). That finally got Messages working and also stopped the constant crashing of identityservicesd and callservicesd. Then slowly I started adding back all the apple preference files in Maybe_Bad (restarting between batches of copies) until I started getting the crashing again. Now the process got a little muddy after a while because of all the back and forthing of potentially problematic files.

I just assumed any preferences containing "ichat" or "messages" needed to be the original Sierra files. In the end I think I narrowed it down to the following causing the problems: com.apple.coreservices.appleidauthenticationinfo.* and com.apple.facetime* (also FaceTime*)

Now I just wish there was a way to export and import messages within Messages.

Answer 4

Thanks, MickM: that provided me the impetus I needed to finally correct that problem on my Mac Pro Sierra server. I had made the mistake of simply accepting the High Sierra upgrade, and when I backed it out ofter seeing how much was broken, it left me with no Messages or iCloud sync and with (literally) gigabytes of log junk about crashing identitysrvicesd and callservicesd. After reinstalling Sierra several times, deleting my iCloud account several times, ripping out ~/Library/Messsages several times, rebooting many dozens of times, and trashing the plists mentioned by the OP several times, I found your post. When I finally deleted the facetime plists, and also in a fit of disgust deleted all the identityservices plists (to let Sierra recreate them cleanly), I was finally able to get it working again.

I don't really care that much about iMessage, but the cloud sync is important to my business- and any Unix system that is generating that much log stuff is seriously sick. It is clear that Apple didn't intend for anyone to back out of that transition... I've now created the files in Applications ("Install MacOS High Sierra.app" and "Install MacOS High Sierra.appdownload", both chmod'ed a-rwx) to keep the App Store from nagging me about High Sierra on any of our machines. Think I'll stay put where I am.

Anyway, thanks for the info. And before anyone else jumps on me: I don't recommend this course of action for anyone who doesn't know exactly what they are doing. It worked for me; but you do this sort of thing at your own risk, with many redundant backups ready at hand. Your mileage may vary. Post no bills...