iMac take 2 minutes to wake from sleep -- SOLVED

[milleron]

For over a year, through a couple of versions of macOS, my 2015 iMac 5k has been taking almost exactly 2 minutes to wake from sleep when it's been in sleep mode for >15-30 min. When it finally does wake, it functions normally. I've found no hypothesized cause and no solutions through several forum posts and Internet searches.
There's a TB2-connected external drive that has an external monitor daisychained to it.
USB connections are just a hub (with nothing permanently attached), an optical drive, and a wireless dongle for a Logitech wireless keyboard, ALL of which were attached during the first 3 years when the Mac "woke" instantly.
Is there a way to use Console to get a clue about what is going on when I tap the keyboard to wake the Mac from Sleep? I've looked at it, but I don't know what I'm looking for.

 

[nambuccaheadsau]

What operating system would be a great start. If using Mojave, have you updated to OS X.14.6 as thewrw was a specific update to this wakwebning problem?

 

[ZipZap]

For over a year, through a couple of versions of macOS, my 2015 iMac 5k has been taking almost exactly 2 minutes to wake from sleep when it's been in sleep mode for >15-30 min. When it finally does wake, it functions normally. I've found no hypothesized cause and no solutions through several forum posts and Internet searches.
There's a TB2-connected external drive that has an external monitor daisychained to it.
USB connections are just a hub (with nothing permanently attached), an optical drive, and a wireless dongle for a Logitech wireless keyboard, ALL of which were attached during the first 3 years when the Mac "woke" instantly.
Is there a way to use Console to get a clue about what is going on when I tap the keyboard to wake the Mac from Sleep? I've looked at it, but I don't know what I'm looking for.

Disconnect the external stuff.. Does it boot normally?

 

[mam8dg]

My guess would be the second monitor. I had the same issue with my iMac Pro when I had a second monitor connected to an OWC Thunderbolt 2 hub. When I connected the monitor directly to the iMac Pro, the problem disappeared.

 

[kohlson]

Another approach to help isolate - create a new user in system preferences, and see if that user has the same wake-from-sleep issue. If so, then it may be a hardware issue.

 

[mikehalloran]

My guess would be the second monitor. I had the same issue with my iMac Pro when I had a second monitor connected to an OWC Thunderbolt 2 hub. When I connected the monitor directly to the iMac Pro, the problem disappeared.

It's a known issue.

No matter what your setup is, there are workarounds. Not knowing your complete setup, I have nothing to suggest.

 

[milleron]

It's a known issue.

No matter what your setup is, there are workarounds. Not knowing your complete setup, I have nothing to suggest.

The complete setup was mostly described in the initial post. The external drive is, indeed, an OWC TB2 Thunderbay. The external monitor (daisychained through the Thunderbay) is a Dell 4K. The iMac is a 5K from 2015. I mentioned the Logitech wireless (not Bluetooth) keyboard. The USB-connected optical drive is an LG.

I did upgrade to 10.14.6 with great hope because it said it was for a wake-from-sleep problem: no joy.

Today, when I get home, the first thing I'll do is connect the external monitor directly to the iMac.

 

[mikehalloran]

Today, when I get home, the first thing I'll do is connect the external monitor directly to the iMac.

What I was looking for was anything connected to the second TB port. Apparently, there is nothing. Connecting your monitor there should fix you up.

If it doesn’t, be more specific than Dell 4K and describe exactly how you hook it up (cables/adapters etc.)

If the issue is solved, then never mind. Whatever works, works.

 

[milleron]

My guess would be the second monitor. I had the same issue with my iMac Pro when I had a second monitor connected to an OWC Thunderbolt 2 hub. When I connected the monitor directly to the iMac Pro, the problem disappeared.

Thanks, mam8dg and others. Connecting the external monitor to the vacant TB2 port did, indeed, make the iMac wake essentially immediately.
The problem is solved, but I'd love to know why waking from sleep was nearly instantaneous for the first three years with the connections exactly as I originally described. Unlike mam8dg's description, this delay did not start when I connected the monitor via the OWC Thunderbay. It started almost three years after I connected it thusly. I can't think that it's anything other than one of the macOS incremental upgrades that came long about 12-18 months ago, because it definitely was not related to the upgrade from Sierra to High Sierra or the one from High Sierra to Mojave.

This is the second time I posted this problem here. Last January, I got no suggestions that were at all helpful. This time, voilà! So, thanks again to all.