Anyone else with no sound in Mail?

I basically followed this article http://www.imore.com/how-make-bootable-installer-drive (as already posted previously) but just checked on a few more additional sites first to make sure the Terminal code was correct (HT201372 was one of them). Getting Sierra was easy, just went to the App Store and downloaded (again as per the article), it confirms the latest as 10.12.4 under "Information" / "What's new..." plus it appears to be the full version (4.95GB in size), I believe the first release was around 4.78GB.

Only tried to boot from the stick which worked ok - not going to use in anger yet because at the moment I'm happy with how the iMac is running, but it's there just in case.

With regards your reply to Dialabrain on whether user info is/can be stored under EFI Firmware or PRAM, I find that unlikely - PRAM (or NVRAM) is an area the computer uses prior to loading the OS, and EFI is just the firmware-based replacement for the PC Bios - so I would not think Apple would allow those important aspects to the boot function to be corrupted by user data (that's just my guess).

I can't think why your method of a clean install would have old data contained in it - just don't think its from the above, but until I try a reinstall suppose I'm not really going to find out.

FWIW, You don't boot into Sierra when you boot from the USB stick. You're booting a USB Sierra installer. It has no complete OS on the Flash drive. From the stick it installs Sierra onto the drive of the Mac. Once it's done installing, you restart the Mac from the newly installed copy of Sierra. At that point you just eject the stick once you finish setting up your new OS.

The whole point of the USB stick is to basically keep your working drive unmounted so it can be "completely" erased - I might be wrong but if you use the Recovery Partition that can't be done because you are still using that part of that drive, it will only erase the section containing the OS itself.

As dialabrain pointed out it's not an alternative source to boot Sierra from but an alternative option as an installer, this article may help https://computers.tutsplus.com/tutorials/the-os-x-recovery-partition-what-it-is- why-its-there-and-how-to-remove-it--mac-… (read the section "Why would I need to delete the Recovery Partition" onwards).

The "USB stick" option in my view should be seen as an additional method to that provided by Recovery Partition or TM and used when those two don't meet your specific needs.

carefulowner wrote:

Would it be true to say, though, that, once you've Sierra on the Mac's drive, the only way of getting back to Mavericks or the former OS is to do a TM restore?

Unless you downloaded a previous version of OSX. If you have, then the installer would be in the Purchased tab of the App Store. In which case you could download it again and create a bootable USB installer for that version.

carefulowner wrote:

Am appreciating your patience and the help you and dialabrain are giving me.

No problem, we are all still learning - read through some of the links and see what you think, I still believe if you use the USB method to clean install the OS you should get rid of a lot of your previous issues - some will remain though which are no doubt true bugs requiring Apple to fix through later point updates (the same for all of us), but overall you should have a better experience (in my view anyhow).

This problem is not initially should I install Sierra, but how do I get my data back on the machine without causing the possibility of further issues. If you have Contacts and Calendar data in the cloud that should come back once signed in, for Mail I would create my accounts a fresh and if required import any old messages from previous saved mbox's. Apps would be treated the same, install from original source and setup a fresh again, even for your printer or other devices. With iTunes it will depend on how you consume your music, for mp3's (take it you have them backed up, not just in TM) just drag them back in - if the cloud just sign-in.

Yes, it's a bit of a pain but a least your Sierra OS will then have the best chance of staying as issue free as possible - that's how I will approach the task if/when I need to spring clean my OS.

carefulowner wrote:

all my mail folders and their contents were miraculously and automatically restored into that account. Don't ask me how! I didn't manually import them back.

That's the puzzle isn't it, but as said previously if you erase the "entire" drive (using the USB stick) which also includes removing the Recovery Partition as well and you don't use TM then that shouldn't be possible.

Also, issues can be caused by corruption or bugs in the OS, all you can hope of doing is limit the corruption aspect, bugs are for Apple to resolve. Now you did previously discuss issues with Mail which I seem to remember could be put under the bug category - but you then discussed more wide spread problems that are possibly down to corruption and if so only a clean install is likely to resolve.

Noted comment but because I could not find any other ref to that suggested method thought better of it - the iMore article was consistent with what others proposed, even a support article from Apple giving the Terminal lines, so felt confident in going with that method.

Came across talk of a program that would also do the same job - Disk Creator, but again thought it better/safer to go with the most widely used method.