iMac takes 22 minutes to start with USBs plugged in

Question

Level 1

12 points

iMac takes 22 minutes to start with USBs plugged in

iMac Retina 5k 27" i7 32/1.12gb Fusion Mac 10.10.5

Starting with Option key, get the normal chime, and takes 22 minutes for the boot manager to show bootable Mac or Windows partitions. This is with hubs/devices in 3 USB ports, and eSata adapters in 2 lightning ports. With just the keyboard plugged in, it takes about 15-20 seconds to get to the bootable partition screen. Once at the screen, either way, computer runs normally.

I have never had to unplug things to start a computer normally. What's up?

iMac with Retina 5K display, OS X Yosemite (10.10.5), bootcamp Win7 Pro

Posted on Jul 18, 2016 6:24 AM

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Answer 1

JimmyCMPIT

Level 7

29,306 points

Jul 18, 2016 6:39 AM in response to soucie1

disconnect the external devices except mouse and keyboard and reset your SMC

Reset the System Management Controller (SMC) on your Mac - Apple Support

then check your system with AHT

Using Apple Hardware Test - Apple Support

reboot and reset PRAM to verify the correct HD is the selected boot device

How to Reset NVRAM on your Mac - Apple Support

then reboot into safe mode

Try safe mode if your Mac doesn't finish starting up - Apple Support

and check the integrity of your hard drive.

Disk Utility (Yosemite): Repair a disk

at this point if you have no issues shut down and reboot normally with the devices plugged, try them one at a time shutting down and connecting and rebooting normally.

if the problem continues you will need to contact the developer of the device(s) that cause the behavior

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Answer 2

rkaufmann87

Level 10

148,534 points

Jul 18, 2016 7:24 AM in response to soucie1

The only way to trouble shoot which device is causing the problem is by a system of elimination. It could be one of your USB devices or hubs or even a cable. You have to elimate the offender, the process could be time consuming until you determine which device it is.

Start with 1 device, a hub and then restart. Next plug in one USB device to the hub and restart, rinse and repeat as needed until you find the offending device. Once found, eliminate or replace that device or it's cable.

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Answer 3

dwb

Level 7

33,298 points

Jul 18, 2016 7:52 AM in response to rkaufmann87

Just adding one thing to this excellent advice. You really need to suspect the hub or the hub and a device is the culprit. In other words a USB device may cause the problem when plugged into the hub but not when plugged directly into the computer. Also when you find the offending device, if it is USB check with a different cable. At work we’ve seen all kinds of USB 3 hub, cable, and enclosure issues. At home I went through 3 USB hubs before figuring out that 1) it was the cable connecting the hub to the computer and 2) I needed to move the hub to the far left of the computer. I’ve seen no issues since.

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