MacBook Pro issues with external drive and usbs

Many Bus-powered drives do not correctly degrade gracefully when the Mac sleeps and drops USB power to standby levels. Instead, they disconnect.

Simple Work-arounds include using independent power supplies for your drives, and

not allowing the Mac to sleep with those drives connected.

mdix44 wrote:

I have an external drive that my MacBook Pro doesn't recognise any more. It sent me a message saying I hadn't ejected it properly although it was still connected and it disappeared from Finder. I tried to use a USB to backup and that worked for a while, then the same thing happened - it disappeared from Finder and I was told I'd ejected it when it was still connected. I tried a second USB and it did the same after about ten minutes. The USB shows up on my son's MacBook Pro using the same connection so the issues is with my laptop.

On an Intel Mac you can try both—

Try resetting NVRAM/PRAM Reset NVRAM on your Mac - Apple Support

(get at least two-three rounds of the chimes when holding the NVRAM Reset)

Try resetting the System Management Controller Reset the SMC of your Mac - Apple Support

"MacBook Pro issues with external drive and usbs: I have an external drive that my MacBook Pro doesn't recognise any more. It sent me a message saying I hadn't ejected it properly although it was still connected and it disappeared from Finder. I tried to use a USB to backup and that worked for a while, then the same thing happened - it disappeared from Finder and I was told I'd ejected it when it was still connected. I tried a second USB and it did the same after about ten minutes. The USB shows up on my son's MacBook Pro using the same connection so the issues is with my laptop."

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External-Powered USB Hub:

Some devices can sustain power off of your Mac, and may crash over a certain amount of time. So, using an external-powered USB hub would be a wise decision when connecting reliable devices such as hard drives that do not have built-in power adapters. For a Mac compatible with macOS 15, a USB-C port would be the right one it. Find such a hub on Amazon: external power usb hub for mac usb c

Consider downloading and running this little "discovery" utility, Etrecheck. It changes NOTHING. Etrecheck was developed by a senior contributor here, and uses mostly system calls and simple tests to collect often-needed information.

it contains little tests for speeds of devices, CPU utilization, memory usage, energy usage and a digest of recent problems, in one easy to use package. it does not even need to be Installed. Because less can be learned when your Mac is running great, best time to run is when your problems are actually occurring, if possible.

if you follow the directions faithfully, its report (pre-laundered of all personally-identifiable information) can be "Shared" to the System ClipBoard, then Pasted into an ‘Additional Text’ window in a reply on the forums.

Use Etrecheck Pro for free:

http://Etrecheck.com

The amount of data you get can be daunting. If you POST your report, some Readers here are willing to look over those reports, and can provide valuable insights.

Then start a reply on the forums, click the "additional text" Icon, and PASTE

you have some kind of weird disk problem, Possibly on the built-in drive.

your drive performance numbers are slow on writes

Performance:

System Load: 2.31 (1 min ago) 2.73 (5 min ago) 2.71 (15 min ago)

Nominal I/O usage: 0.00 MB/s

File system: 16.73 seconds

Write speed: 956 MB/s

Read speed: 2015 MB/s

My 2015 with a 512 drive tests about 1900 for read and write.

your installed Rogue amoeba ACE is not signed, an indication it is very old version.

I am not happy to see fan control add-ons

Sierra wireless does not even use that name any more, and those drivers may also be very old

do your REALLY have a blackberry still connected?

My recommendation:

it may be time to erase your Mac and re-install MacOS, and add back your Files but NOT your Applications and extensions. Ye-load your added Applications and add-on that you really need from fundamental sources.

OF COURSE you need trusted backups to do this.

Barney-15E suggest in this nearby discussion that as drives age, they can draw more power than they are supposed to:

External hard drive does not mount when I… - Apple Community

This is occurring across many different drives, with different cables. Yes, I've lost data! I found NVRAM reset has helped, but am still getting the 'Disk not ejected properly' after reset, but the drives are still connected. I know people using current generation M series Macs having the same issue, so in that case it's not an NVRAM issue.

Macbook Pro 15" Intel - macos 12.7.6

Thanks! The issue occurs with drives that have their own power supply, as well. It also is not an issue with sleep as it occurs when the drive is in use, and the settings are as follows:

AC Power:

 System Sleep Timer (Minutes): 0

 Disk Sleep Timer (Minutes): 0

 Display Sleep Timer (Minutes): 30

 Wake on AC Change: No

 Wake on Clamshell Open: Yes

 Wake on LAN: No

 AutoPowerOff Delay: 259200

 AutoPowerOff Enabled: 1

 Current Power Source: Yes

 Display Sleep Uses Dim: Yes

 Hibernate Mode: 3

 PrioritizeNetworkReachabilityOverSleep: 0

Just happened now, and both volumes are still mounted.

Thanks for looking at that, Grant, I will try a reinstall, without using Migration Assistant as I have been doing for 20 or 25 years. Definitely time to start fresh and I did get two good backups. Will let the community know if that solves things.

I'm plugged directly into the USB port, no hubs or anything. Both USB ports have the issue.

Actually the volumes do unmount, and then remount after 5 seconds.

When I ran EtreCheck Pro yesterday, no major issues were found. Today it is reporting kernel panics.

Thanks so much for your help!

You can use Migration Assistant, just don't re-install everything.

Migration Assistant WILL let you select just your files.