Not sure if something is wrong with iMac since Mojave install.

Tommy c

macrumors 6502
Original poster
Sep 9, 2012
339
210
Pocono PA
I'm sorry I'm posting this, but can't seem to find anything solid. Im running a Samsung 512GB External SSD with USB 3.0 on a 27" iMac for booting up. I have not upgraded the internal HD to Mojave, it is still on HS.

Now, when I turn the computer on, I have a blackish screen for 60 seconds or so. It feels like forever lol. Then the Apple logo comes on and it starts booting up. Sorry if it sounds retarded that I'm asking if it's normal. It consistantly boots up this way now.

Is this 60 second wait time normal with Mojave? The computer used to boot up in 18 seconds flat with HS on the External SSD. Now, it is more like 1.5 minutes. Not that It's bad, but that is really slow from what it was. I' can't figure out what's wrong other than calling Apple support. Any help is appreciated.


Thanks,
Tommy
 

chscag

macrumors 68040
Feb 17, 2008
3,693
1,269
Fort Worth, Texas
In comparison, I have a 512GB Samsung T5 SSD attached to one of my Thunderbolt 3/USB 3.1 ports on my 2017 27" 5K iMac and it boots almost as fast as the internal SSD does. Both have Mojave on them and of course formatted to APFS. Is your Samsung external SSD formatted to APFS or HFS+?
 

Tommy c

macrumors 6502
Original poster
Sep 9, 2012
339
210
Pocono PA
In comparison, I have a 512GB Samsung T5 SSD attached to one of my Thunderbolt 3/USB 3.1 ports on my 2017 27" 5K iMac and it boots almost as fast as the internal SSD does. Both have Mojave on them and of course formatted to APFS. Is your Samsung external SSD formatted to APFS or HFS+?
How do I know what it is formatted to? When I bought this computer, I bought the external HD and did the cloning stuff and what not. I'm not computer savvy, just enough to get by. When I updated to Mojave, I did it directly to the external HD since it's what I boot from.

Where do I see how it's formatted?
[doublepost=1538792426][/doublepost]Ok, I figured that out. APFS, is this good or bad?
 

MacUser09

macrumors 6502
Sep 26, 2009
250
18
UK
I'm sorry I'm posting this, but can't seem to find anything solid. Im running a Samsung 512GB External SSD with USB 3.0 on a 27" iMac for booting up. I have not upgraded the internal HD to Mojave, it is still on HS.

Now, when I turn the computer on, I have a blackish screen for 60 seconds or so. It feels like forever lol. Then the Apple logo comes on and it starts booting up. Sorry if it sounds retarded that I'm asking if it's normal. It consistantly boots up this way now.

Is this 60 second wait time normal with Mojave? The computer used to boot up in 18 seconds flat with HS on the External SSD. Now, it is more like 1.5 minutes. Not that It's bad, but that is really slow from what it was. I' can't figure out what's wrong other than calling Apple support. Any help is appreciated.


Thanks,
Tommy

I think there may be a bug in Mojave causing this. There are other threads talking about this happening. I get it myself, on my 2015 Macbook Pro, including the black screen and Apple logo. Will probably be addressed by Apple in the next update.
 

DeltaMac

macrumors G4
Jul 30, 2003
10,235
2,688
Delaware
...
Now, when I turn the computer on, I have a blackish screen for 60 seconds or so. It feels like forever lol. Then the Apple logo comes on and it starts booting up. Sorry if it sounds retarded that I'm asking if it's normal. It consistently boots up this way now.

Is this 60 second wait time normal with Mojave? The computer used to boot up in 18 seconds flat with HS on the External SSD. Now, it is more like 1.5 minutes. Not that It's bad, but that is really slow from what it was. I' can't figure out what's wrong other than calling Apple support. Any help is appreciated.
...
I would do two steps:
Reset NVRAM, then boot to your external drive through the Option-boot screen.
The NVRAM reset will remove your boot disk setting --- Set your System Preferences/Startup Disk, so your external boot drive is selected.
That may help your longer-than-expected boot times.
 

Larspj4

macrumors newbie
Oct 6, 2018
3
0
I also have issues with my late 2013 iMac with a 3tb fusion drive.

It just doesn't turn on anymore.

Maybe 1 out of 15times it will turn on, but mostly it just spins up the HDD and then nothing.

Can't believe they release this software
 

chscag

macrumors 68040
Feb 17, 2008
3,693
1,269
Fort Worth, Texas
I also have issues with my late 2013 iMac with a 3tb fusion drive.

It just doesn't turn on anymore.

Maybe 1 out of 15times it will turn on, but mostly it just spins up the HDD and then nothing.

Can't believe they release this software
Maybe you need to run a disk check first aid on your fusion drive? I would not be in a hurry to blame Mojave especially when it comes to a fusion drive that's going on 5 years old. Remember, that when you installed Mojave it also reformatted your fusion drive to APFS. Run a disk check and let us know.
 

Larspj4

macrumors newbie
Oct 6, 2018
3
0
I did manage to run a disk check, and no issues came up.

I couldn't run the disk check in recovery mode. The HDD was greyed out then.

I don't know what the issue is. But the new APFS format sounds like the issue.
 

Eddy P

macrumors newbie
Oct 7, 2018
4
0
BE (Antwerp)
Yes, it seems indeed all related to the new APFS filesystem, as I restored Mojave to a HFS+ journaled volume and all slowdowns during boot are vanished ! Down from 4 minutes to... 20 seconds on my boot SSD :) , Mojave now running smoothly like Sierra always did... It's kinda cumbersome to revert the bootdisk back to HFS+, as it involves to make 2 clones with SuperDuper! - the first to a temporary free partition (e.g. like a HFS+ pre-formatted external disk) and the second back to a HFS+ re-formatted bootdisk ! But for me it was all worthwhile. :)
[doublepost=1538929448][/doublepost]By the way, now that I'm back to HFS+, new backups with Time Machine are also flawless ! ;)
 
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