Slow starting iMac

[clyde]

iMac 14,1, OS 10.10, 480 GB Mercury Electra SSD from OWC.

Symptom: Press power On button, iMac chimes. Nothing happens for 36 seconds. Then the Apple logo appears and the progress bar runs across the screen. (When working correctly the Apple logo appears immediately after the chime.)

After that it seems to be OK. This started a couple days ago. Finally ran through the process three times; the 36 second delay is consistent at start.

Had the OWC SSD installed mid-March 2017; has been fine until this, and still seems to work right—when it finally starts.

Only clue—within the last few days the house reaches 80°F…

[GGD]

Is the boot drive selected in the Startup Disk system preference?

When you say "nothing happens" does that mean that the screen doesn't even come on, or it's on, but no sign of booting?

Might be running it's power on self test, how much RAM does it have?

[clyde]

The boot drive is the internal SSD, and it is selected.

"Nothing happens" means the screen is black. There's no sign of life.

8 GB RAM. Has worked fine since I got it and had the SSD installed.

As to power-on self-test—never saw this delay before. Soon as the chime sounded the Apple logo appeared and the progress bar zipped across.

[GGD]

This might actually be a situation where "Reset PRAM" has a chance of doing something. You might need to re-select the startup drive after doing it.

In case you've never done it, hold down CMD-OPT-R-P at boot until it gives you a second Boot Beep.

[jdc]

GGD wrote:
This might actually be a situation where "Reset PRAM" has a chance of doing something. You might need to re-select the startup drive after doing it.

In case you've never done it, hold down CMD-OPT-R-P at boot until it gives you a second Boot Beep.

Yup.

You can also shutdown, unplug from wall, wait a few minutes -- replug, restart.

[clyde]

Thanks, GGD and jdc. Did as you directed—now the Apple logo appears five seconds after the chime.

Any idea why the PRAM was awry?

[GGD]

clyde wrote:
Thanks, GGD and jdc. Did as you directed—now the Apple logo appears five seconds after the chime.

Any idea why the PRAM was awry?

I think Apple messes with it to do funny things at boot when doing OS updates and installs, and firmware updates, where it reboots itself to complete the operation. Only guess is that something got interrupted or they didn't clean-up and restore things to normal correctly.