macbook won't find external drive, yet imac does

[zeppo2]

and the macbook does find my other external drives no problem

This first began with one USB port and then the other.

The drive does not show in DiscUtility either

I can view the drive on my iMac.

I can try resetting the SMC . But it doesn't seem like that should be the issue when the ports recognize other external drives without issue, and the problem external drive is recognized without issue on other macs.

Any thoughts?

 

[chabig]

It would be nice to know the details of your machines. What exactly are they other than "Macs" (model, year, etc)? Also, what is the format of the external drive? What is the interface (USB 2, USB 3)? Are you using the same cable?

 

[zeppo2]

It would be nice to know the details of your machines. What exactly are they other than "Macs" (model, year, etc)? Also, what is the format of the external drive? What is the interface (USB 2, USB 3)? Are you using the same cable?

WD MyPassport USB3 for Mac , same cable, have been using the drive without issue on both the iMac the macbook for a couple of years.

Late 2009 iMac
late 2014 macbook pro retina

 

[chabig]

Thanks. I assume then, that the drive is formatted with HFS+. Let's review what you know:

Both Macs support USB drives. There is nothing you can change here.
Both Macs support HFS+. There is nothing you can change here.
Both Macs work with other drives, just this one is trouble, and it only recently began.
You're using the same cable--try a different cable.
Isn't the MyPassport a portable drive? If so, try powering it with AC. Perhaps the MacBook Pro isn't supplying it.

Other ideas: Connect the drive to your iMac and run Disk Utility first aid on it.

 

[Fishrrman]

OP:

What OS is on the MBP?
What OS is on the iMac?

chabig's suggestion about using AC power with the drive (when connected to the MBP) could be "the solution".
It's possible that the MPB isn't supplying enough "bus power" to get the drive up-and-running.

 

[chabig]

It's possible that the MPB isn't supplying enough "bus power" to get the drive up-and-running.

And that might be because the hard drive inside is beginning to go bad and requires extra "oomph" to get going. At least that seems more likely to me than both MacBook Pro ports going bad.

So OP, if the drive works with AC power, consider that it might be starting to fail and make sure that you keep that data backed up. Also consider that a bad sign and consider replacing the drive.

 

[zeppo2]

And that might be because the hard drive inside is beginning to go bad and requires extra "oomph" to get going. At least that seems more likely to me than both MacBook Pro ports going bad.

So OP, if the drive works with AC power, consider that it might be starting to fail and make sure that you keep that data backed up. Also consider that a bad sign and consider replacing the drive.

[doublepost=1546447513][/doublepost]Well, I guess I also should have mentioned that the problem exists with the macbook plugged in to AC. Before posting here I googled and that was one of the suggestions I found.

Can't run DiscUtility because it is not found in DiscUtility, right? Or is it possible to do this somehow (honestly, I'm a novice).?

Can I do SMC reset on Mid 2014 Macbook Pro Retina 2.6 GHz Intel Core i5 with shift+cntl+option method ? I don't think it has a removable battery, but I don't know what it looks like to have a removable battery (you would have to unscrew the back) and the pages I've found detailing which have it and which don't are unclear to me. Page says MacBook (Retina, 12-inch, Early 2015 and later)
https://support.apple.com/en-us/HT201295
yet it really doesn't look like mine is removable
[doublepost=1546447662][/doublepost]iMac El Capitan
macbook High Sierra

 

[chabig]

Can't run DiscUtility because it is not found in DiscUtility

You said it works on the iMac. Run Disk Utility on the iMac.

the problem exists with the macbook plugged in to AC

That doesn't matter. The MacBook USB port might not supply enough power. Plug the drive into AC.

Can I do SMC reset on Mid 2014 Macbook Pro Retina

You can, but according to your linked document, the SMC doesn't have anything to do with the USB port.

 

[zeppo2]

The drive is USB powered. I'm running the First Aid on it via the imac now. We'll see. At any rate, I'll be transferring the data to a new drive and start using this for other things (most of it is already backed up). But the fact that the macbook works with other My Passports with no problem and that the problem drive works on the iMac, and that it failed to work on one USB drive first and then a day or so later started not being recognized on the 2nd USB drive on the macbook, all this makes me wonder if there is a software issue here, and is it something malicious. But as a novice, I may be more paranoid than is due.

 

[Fishrrman]

If you have a replacement drive on order, use that one on both Macs.

Just keep and use the "problem" drive on the iMac, if it works ok there...

 

[zeppo2]

ran DiscUtility first aid via imac and it passed with flying colors
[doublepost=1546453929][/doublepost]

You said it works on the iMac. Run Disk Utility on the iMac.

That doesn't matter. The MacBook USB port might not supply enough power. Plug the drive into AC.

You can, but according to your linked document, the SMC doesn't have anything to do with the USB port.

The list of issues SMC might address is not comprehensive, but as I understand it, the symptoms of problems that the SMC reset may fix are hardware function related.

 

[chabig]

ran DiscUtility first aid via imac and it passed with flying colors
[doublepost=1546453929][/doublepost]


The list of issues SMC might address is not comprehensive, but as I understand it, the symptoms of problems that the SMC reset may fix are hardware function related.

You can try. It hurts nothing. But as you only have one drive with a problem, and all other drives work fine on both machines, I think the odds point to a bad drive rather than software.

 

[zeppo2]

You can try. It hurts nothing. But as you only have one drive with a problem, and all other drives work fine on both machines, I think the odds point to a bad drive rather than software.

But why would the problem drive work on the imac then?
[doublepost=1546457770][/doublepost]Well, SMC reset did nothing. However, NVRAM reset did restore recognition of the drive by one of the USB ports (the one that was more recently functioning before it went out).

Then, it occurred to me that while I was using the same cord with the problem drive with the macbook (where it wasn't found) and the imac (where it did mount), I was using a different cord for the other drives that were working with the macbook. When I used that cord with the problem drive, the macbook did find the drive ok with both USB ports.

I'm just going to speculate that it is a combination of a weak cord in some respect and a weak USB port.