Model A1419 / Late 2013 / 3.2 & 3.4 GHz Core i5 or 3.5 GHz Core i7 Processor, ID iMac14,2

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Why on Power On takes long to show Apple Logo?

Hi everyone,

Does anyone know why it takes about 10 seconds (black screen) to show Apple Boot Logo in iMac 27 2013?

I got macOS Catalina on non-Apple PCIe SSD with adapter.

I’ve pointed out the Startup Disk in Settings as a Boot Disk - done reset and……… it was showing that Apple Boot Logo right away - but from shutdown - power up - it takes about 10 seconds to show Apple Boot Logo - which is very weird.

I got even macOS Catalina installed on genuine Apple HDD (without any PCIe SSD) and STILL same thing.

I had 27” iMac but 2012 with same non-Apple PCIe + adapter SSD and it was showing Apple Boot Logo right away.

I’ve hold D for Diagnostic and no errors at all.

I’ve done PRAM reset.

Thank You


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Give this a try: Go into your Date & Time settings un-check the time server setting and manually set the date and time so its correct. Now disconnect the power cord for the night (longer if you can). In then morning plug in the cord and check the date and time is is correct?

If not the PRAM battery is bad. So your settings are not being held so the polling proves takes place instead of what you defined. You’ll need to take the logic board out again as its on the back side iMac Intel 27" EMC 2639 GTX 775M GPU Logic Board

Block Image

As to why it drained, I’ve seen some issues with the M.2 adapters its also possible it was just bad.

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iMac Intel 27" EMC 2639 GTX 775M GPU Logic Board



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INTERESTING idea - Thank you Dan - I'll do this today


Sadly Dan - it cannot be battery - I've done all those steps (un tick set time automatically - remove cord - iMac off for 1.5 days - I even discharged capacitors pressing power on button when it was disconnected)

........and today I got correct time :(

Very weird.

If not that genuine Apple HDD which was giving same problem I would think that new PCIe + adapter SSD is doing this - additionally iMac does not give any issues while Diagnostic boot.

2x 8GB RAM would do this? Like more RAM = longer test on boot?

I remember I had Mac Pro 2009 with 8 RAM modules - the more RAM I installed - the longer "white screen" before Apple Boot Logo showed up - but not like in this iMac 2013 - like even 15 seconds.

It is annoying because macOS loads up is same time as I wait to even start to boot up :(


@Bart - Well ... You have the right idea it would take longer if Apple followed the same approach, but they don't.

Modern systems use a check once during POST when the RAM value has changed and records the new value. So for some reason the setting is being lost forcing the system to recheck the RAM during POST.

Basically, it shouldn't take a big difference like you're stating here. This is one of the PRAM (NVRAM) settings. The clock test was to make sure the battery wasn't the issue.

Time to visit an independent shop with component level and micro soldering skills or an Apple Store as there is something very odd here.




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