How to fix unresponsive USB ports on iMac after updating?

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Level 1

4 points

How to fix unresponsive USB ports on iMac after updating?

imac late 2013 27in I got recently second hand. Everything has been working fine up until last night when it told me I needed to update it. I updated it and now the usb ports aren’t registering my keyboard or my mouse and of course since I can’t log in it won’t register my Bluetooth apple mouse I had as a backup. I unplugged it then plugged it back it attached my keyboard and mouse and during the boot up they lit up but immediately when it showed my Home Screen they went dead again. Neither the keyboard I have nor the apple one given to me work. Just a bit confused on how I can even go about fixing it as I can’t unlock it now or even properly restart my computer. Any help would be great thanks! (Again none of the usb ports aren’t registering once the lock screen boots up)

[Re-Titled by Moderator]

Original Title: Updated IMac late 2013 now no usb ports on the back register my keyboard or mouse to log in.

iMac 27″, macOS 15.7

Posted on Sep 7, 2026 1:19 PM

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Answer 1

MrHoffman

Level 10

162,905 points

Sep 7, 2026 2:08 PM in response to NikkiC173

Connect another keyboard and mouse to the Mac using their charging cables, disconnect all other connected gear, and leave the keyboard and mouse connected. I’d also try charging the keyboard and mouse if rechargeable, or replace the AA batteries if not.

If that wired connection (sorts, kinda) works, reset both the SMC and NVRAM, as a first test:

This may be a faulty Mac, as well. Maybe excess power draw, if there are other USB-connected devices.

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Answer 2

Sep 8, 2026 2:39 PM in response to NikkiC173

What version of macOS were you running before the update and what version of macOS was being suggested for the update?

Your signature on your post indicates macOS 15.7.....is that correct? If so, then your Late-2013 iMac is using a hacked copy of macOS which is against the Apple licensing agreement. With those hacks people cannot even install minor macOS update patches without breaking the flimsy hacked installation.

If this is the case, then to reinstall a legitimate legal and compatible copy of macOS onto this iMac requires a couple of very specific steps in addition to the normal procedure for erasing & reinstalling macOS. Restoring some data which utilizes libraries (iTunes, Photos/iPhoto, Mail, etc.) cannot be restored to an older OS.

FYI, macOS 10.15.x Catalina is the last supported version of macOS for a Late-2013 iMac.

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Answer 3

MrHoffman

Level 10

162,905 points

Sep 8, 2026 6:56 AM in response to NikkiC173

If you can’t get as far as even SMC and NVRAM resets, or Safe Mode, you’re headed for a diagnostics and repair discussion with Apple Support.

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Answer 4

NikkiC173 Author

Level 1

4 points

Sep 7, 2026 9:02 PM in response to MrHoffman

So I actually tried using the original keyboard it came with as my other is a gaming one that lights up, the original apple keyboard isn’t being Registered either. The ports very obviously work as my gaming keyboard lights up during the initial reboot (apple icon/loading screen) then once it’s on the lock screen to get into the computer it no longer lights up and nothing plugged in works.

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