iMac screwed up - upgrade to 4K

OK, found something that my explain this puzzle.

The latest Mojave has some changes that can conflict with the LG Ultra HD Deep Color mode.

Others have posted complaints about this recently, but Apple hasn’t fixed it yet.

In the meantime, apparently just switching off LG Ultra Deep Color mode on the specific hdmi port you use with the mini can fix it.

Others have reported good success with this.

Let’s try this and see if the fix works.

That fixed it.

Mini + LG 4K TV are online and working properly now.:+1:t3:

The issue was a recent Mojave change that conflicts with the ultra deep color feature of LG TVs.

The feature should be defaulted to off, but if it’s turned on, it will cause a black screen with the latest Mojave release.

Until apple updates Mojave to auto-detect this, the work-around is simply to toggle the ultra deep color mode on the LG. That fixed it right away.

Since the LG had arrived a week before the mini, dbk couldn’t first just try the tv + mini with the default settings. By the time the mini came, the settings may have already changed, while experimenting with his older Mac.

In addition to apple fixing Mojave, LG needs to adjust their ‘restore to factory settings’ function to also clear this setting. Dbk had wisely tried that, suspecting he may have caused a configuration conflict, but apparently the restore function didn’t catch this particular setting.

The LG TVs in the Apple store clearly were set to the right state, so they worked straight away. But the Genius Bar staff was not aware of this Mojave conflict, and couldn’t suggest this correction. The LG in Best Buy must have had its ultra deep color mode set on like dbk’s TV, so it showed the same issue.

So, kind of a weird cascade of stacked, subtle, config conflicts and firmware quirks, but all is good now.

Both TV and Mini are working perfectly. No returns needed.


Below is a recent macrumors forum post discussing this same issue.


Looks like Mark found the solution, though LG made things difficult. First, the location of the Ultra Deep Color mode was in a submenu under “Picture” rather than in “General”.

Also, as you can see in the popup in the picture he posted, the comment says "Turn on/off ULTRA HD Deep Colour for HDMI1 port. But it says the exact same thing whether it is presently on or off. You will also see in the picture that under HDMI1, it says “On”, but on my LG it doesn’t say anything! There is a slider image to the right of it and each time you press the “ok” button on the remote, it will move the slider - but nothing actually tells you it is on or off! Strangely, when the slider switch brightened (which I would assume as “on”, that’s when things worked. But it’s only supposed to work if it is “off”. So I guess my interpretation is wrong. LG really needs to work on their UI!!!

After we got it working (at the time, the LG was on the floor to make room for my other stuff I had to use instead), I had to adjust the “underscan” since I couldn’t see the menu. No big deal, but when I moved everything back to my desktop and booted back up, it wasn’t showing the menu again. So I opened up display prefs again - it was still where I had put the slider yet wasn’t showing properly. I clicked to get it closer to zero (where it was originally) and it actually got better. So somehow LG wasn’t retaining something. I then put it back around the second marker and it’s fine. Eventually I’ll test to see if it keeps messing up on a reboot or not (or maybe it is only if the LG is turned off too).

So, now I’m down to trying to solve my email account issues. Found instructions for moving it manually so we’ll see if that works or not. I think the other stuff (updating apps, etc, won’t be too difficult. I’ve already done some I use regularly, but I definitely need mail straightened out before I’ll feel comfortable.

Thanks again, Mark!


Reading through that thread you linked to, some of them referred to turning HDR “on” to solve the problem. Not sure how that ties in with the “Ultra HD Deep Color”.

Tomorrow I may look at setting the port to game and changing the name of it to “PC” since someplace I said at least one, maybe both, of them needed to be done to successfully get Chroma 4:4:4. But I think I’ll just leave the rest alone for awhile!

And if I only change those two things, I should be able to go back easily if anything screws up.

Okay, display still fine, but not out of the woods yet because of the mail.

Following instructions for manual moving - tens of thousands of files in the Mail folder in the Library, b it didn’t seem to do anything.

I did go to mail Accounts afterwards and selected Google to add an account. I still don’t understand this, but my main iCloud account is the same google address. And I had a gmail account that referenced Game Center. So I was essentially entering the same address this time! But it worked to get those emails to show up and the mailbox to show under the inbox. I’m going to try something and be right back.

May finally have gotten it to work! Though my idea I just tried wasn’t successful. I decided to reboot thinking that just maybe that had to be done to have it read the stuff I copied in. Well, it didn’t change anything.

So I went to Accounts again, chose “add other account” and from the next menu chose “Mail account”. Just like all the other times, when I entered the address and password, it said the password was invalid.

So I went back to the other option I’ve done before and chose “iCloud”. But, for whatever reason, this time it didn’t say it was invalid and now it does show up in my inbox! I’ll still have to run some basic tests (and compare mailboxes with my other computer), but it is progress at least. Though I still haven’t gotten all the folders I set up to save mail in. For example, I have a folder for all Treg communication. Maybe I’ll try exporting and then importing one and see what happens - probably tomorrow.

Absolutely no idea why it worked this time. Couldn’t have been the reboot since I’ve done that before. Could be transferring the Mail folder had some effect on that. More likely I now also have garbage in there that isn’t necessary, but if that is the only element that isn’t “clean”, I can live with that.

Now, since I rebooted, I also have found that the screen setting gets messed up each time. I rarely reboot by computer so, while annoying, it normally won’t bother me. I did try just turning off the TV and back on as well as putting the screen to sleep and waking it back up and that didn’t change the screen.

Here’s a question I’ve wondered about for years about Contacts so, with the transferring to a new computer, this is a good time to get answers!

In the past I’ve had contacts in the cloud, but also “on my Mac”. As I recall, my reasoning was that I wanted copies on my Mac in case I didn’t have an internet connection. But how it actually works is apparently not how I thought it works because the number of contacts on each often would not match and it was a pain to find which ones were missing and copy them over.

So, right now the new Mini only has the iCloud version plus one “on my Mac” (my own contact card).

Is there a way to simply have everything in the cloud also on my Mac - and if I add one to either the cloud or Mac, have it automatically copy to the other? Sort of like I keep copies of all my photos on my Mac, even though they are also in the cloud.

I think the “On my Mac” cards mean “only On my Mac” and the “On iCloud” means it is on both your Mac and on iCloud, and synced. The way iCloud works for most things is that there is a copy saved on your device or Mac, and also uploaded to iCloud, and changes on one will update the other.

This is why when you turn off iCloud it asks you if you still want to keep the local copy.

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Oh, that would be perfect then. Thanks.

Re - references to HDR on macrumors posts - this illustrates an interesting phenomenon.

This is a point of confusion by poster Cell-666.

The first post by Gigatoaster correctly points to a conflict with the Ultra HD Deep Color mode, which the screen cap shows. This feature is related to, but not the same as HDR, or High Dynamic Range.

Cell-666 then refers to the setting as HDR, conflating Ultra HD Deep Color with HDR, which is a misnomer.

The next poster then uses the same setting in the screen cap with success, but then adopts the same handle as Cell-666 to report it - HDR - instead of the correct moniker - Ultra HD Deep Color, or UDC.

The subsequent posters are changing the setting they saw in the screen cap, but calling it what cell-666 called it - HDR, instead of what it is - UDC.

With so many wrong references to HDR, readers who don’t take time to piece through the chronology won’t see where it goes wrong, and just try HDR, which doesn’t work, depriving them of the fix. It’s sort of like the childhood game of telephone, where serial coloring of a statement upends its meaning.

This is why when leveraging forum posts, some engineering logic is often needed to precisely discern the actual underlying cause from casual statements.

The real nuggets of truth were the jpg of the correct LG menu setting, from Gigatoaster, together with the confirmation from cell-666 and Shamhead that it worked. But you have to independently infer that the name he called it - HDR - was simply wrong.

User forums are fantastic tools to get community help, but casual comments can have errors in them. To leverage these reports, you must rely on very careful logic, and the discipline of scientific principles, (only believe what the data supports) to weigh the relevant facts and get to a core understanding.

In a process like treg, this logic-based approach has been used extensively to resolve edge case details. We may have an initial hunch about why something may occur, but we need to be open to other causes, and get solid data to corroborate the right resolution.

This logic really works, and is why the many contributions of treg users have produced a machine that performs well today.

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Similar to @colinng’s note about cloud vs On My Mac, there is an issue about email folders being cloud vs non cloud that’s important for migration.

I have not been reading all of the above messages closely enough to know if this exactly matches your situation @dabigkahuna but I think it’s important enough to mention anyway.

There are IMAP type mail accounts which store folders, and also folders stored in a section called On My Mac which is totally local to your computer. (there are other kinds like POP etc but I doubt you have those).

If you’ve been reading about migrating mail folders, and if it has to do with moving certain library folders from your old Mac to the new one and then importing in the new mail program, this is ONLY needed for your On My Mac folders. There are also library folders for your IMAP accounts in your library, but they are both not necessary to move (for reasons I’ll describe next paragrap) and also not guaranteed to be complete. An IMAP account is a cloud based mail account and most mail programs don’t even bother to keep a 100% full complete copy locally for you. They cache tons and tons of messages locally to improve performance but that doesn’t mean it’s a complete set.

Because an IMAP account is totally cloud based, your mail program is considered a client for each of those accounts. It’s basically a window into that account where you can see all the mailboxes/folders, move things around, compose, delete, mark messages. When you go to a new device you give it all of the credentials and server addresses for that account and then it automagically synchronizes and lets you begin using the account. You can access the account on multiple devices (i.e. from multiple clients) and they’ll each give you a window into the true IMAP account that lives on some server somewhere, and they’ll each cache some or even many messages locally to keep the responsiveness seeming quick.

So mail migration involves ONLY moving the On My Mac folders, and then just adding credentials for all your IMAP accounts. Then usually a few other things like choosing settings on how your mail app behaves.

I was rereading them for the third time when I woke up during the night, trying to sort that out as well as figuring out whether it should be on or off - because those saying HDR kept saying “on”. The guy who used the right term showed a screen with it “on”, but was not clear about whether that was the right setting or if you should follow the other info on screen which said you could turn it on or off.

I have no way of being sure on mine since it never actually says on or off, but if my feeling that the brighter sliding on/off button is “on” in that state, then it isn’t that Ultra HD Deep color needs to be off, but rather it needs to be on. This would also fit those who said HDR needed to be on, but really meant Ultra HD… needs to on.

Icons can be good, but sometimes words just work better for clarity!

Yeah, LG could certainly use some refinement to their menus,

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I remember the account I was trying to duplicate said “map” on my old machine. But, as part of my work, I managed to mess up and change the main account password for my Apple ID. And further work to figure things out I noticed I had the outgoing mail server options both were to old stuff that I no longer have and haven’t had for years. This mystified me as no others were shown. But I removed those two - and suddenly I couldn’t send any mail. In the process of trying to fix that, I ended up making it an iCloud account. Frankly, I was going through so many issues, I can’t remember anything more than that. It’s one of the reasons I’ve always just used super duper to clone the old system to the new the past.

I did save a copy of the old preferences for mail as well as the mail folder the new machine had before I replaced them. I could copy them back, which would save a lot. It’s only 27 MB compared to the 609 I copied over! But then, will doing that lose my account I just got working!

With respect to my prior note, anything that’s not in the On My Mac section of your Apple Mail sidebar on he left is a cloud account that fits into the category of IMAP for the purposes of my note above.

The fact that it had outgoing server options reinforces that it’s a cloud account. Also the fact that the folder is so much smaller than the one on your original machine is related to the “caching” I mentioned about IMAP accounts. The important thing from what I’m trying to say is that you DON’T want to copy imap folders back and forth between machines. Instead you want to put in the same credentials, and then use the Mail app to browse those folders to assure yourself whether they seem to have the same number of messages. Don’t worry about the size of the files stored on your hard drive because IMAP accounts don’t store everything there.

The problem was, I couldn’t recreate the credentials for that folder because it kept saying the password was invalid - yet the same password worked to access it at! And I tried entering it both manually and via my TB macro which worked elsewhere. It might have been coincidence, but it only worked after moving those folders. Now I have to decide whether to put the old folders back and, if it does remove that account, see if I can recreated it again. Very worrisome!

Meanwhile, the mail stuff I do not have showing at all would be in folders I created listed under “On My Mac”. Haven’t tried exporting and importing for those yet and I’ll be out for awhile. and iCloud are not exactly the same thing. Apple’s been pretty twisted with their history of iTunes, Apple, iCloud,, app stores, etc addresses. I’m also still a bit confused about your description of using gmail to log in to Apple (which is possible for making purchases, but I would guess not for Mail services).

But here’s one thing for sure, that you can easily try:

IF you go to and successfully log in, and click the Mail icon, and see some of your mail there, THEN you can go to your Mac System Preferences -> Internet Accounts and hit the “+” at the bottom, then click iCloud to add the same iCloud account and it will give you all those same mailboxes in your Apple Mail app. One twist: IF this is the same login you use in the iCloud panel of Sytem Preferences, then it’s already added to Internet Accounts and you just need to check the box next to “Mail” for that account.

Similarly, IF you go to and successfully log in and see some of your mail there, THEN you can go to your Mac System Preferences -> Internet Accounts and hit the “+” at the bottom, then click Google to add the same google account and it will give you all those same mailboxes in your Apple Mail app. Google will try to bug you immediately or later about scary security warnings but they just don’t want you using Apple’s mail app! :slight_smile:

If you have other mail accounts at other services, you will typically use the “add other account” option after hitting the “+”, and after failing at first login attempt you’ll be taken to an advanced form where you can enter all the server (IMAP & SMTP) and ports info that the other service lists for you somewhere in their support pages.

Hope this helps …

p.s. All of this without ever transferring mail folders between computers. The folders EXCEPT FOR THE On-My-Mac ONES, should show up automagically.

Okay, I’m back. I can see my mail at the iCloud and gmail for their respective accounts. Of course, I already, somehow, managed to get them on my Mac (except for the “on my Mac” folders) already so that doesn’t prove much. But I had gone to which sure looks like, and log in successfully when I couldn’t get that account on my Mac because it wouldn’t accept the same password. I don’t recall if I actually looked at the mail in the cloud (I think I did though).

Basically, there seems to be no logical reason why I couldn’t create it in many many attempts, but suddenly I could and the only change I know if was copying those mail folders over manually.

I may try copying what I have now on the Mini for the mail folder and mail prefs, then take the versions of those that I made copies of before overwriting them, and see what I get. If the account isn’t there as a result, try again to recreate it. If that doesn’t work, paste in what I have now again.

And hope I don’t screw things up!

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