External HD doesn't show up on Pro but does on Air

[brobson]

I am in an almost panic.
I have 1T worth of lesson plans for the last 18 years on a 5T Seagate External HD.
The ridiculously fragile plug in failed when I dropped it but there was no problem, I had all of the info on a spare computer (2011 MacBook air that I bought here-greatest purchase ever) it has El Capitan 10.11.6.
So I bought a new Seagate and proceeded to drop it again. I managed to put it back together but voided the data recovery policy I bought by doing so and taped the tiny plug to it with duct tape.
Everything was fine, I bought a hard case and it works well. Now suddenly it stopped working on my 2015 MacBook Pro. It is also running El Capitan. I thought it was the external Hard drive's fault since I had messed with it but it works fine on the macbook air.

So I have new stuff on the HD so I thought I would just (gulp) wipe the info on another Seagate 3T External HD and transfer everything back on it (as a back up to my backup) in case the HD was about to be gone.
I tried to transfer and I keep getting error messages about a particular file, etc. or that I need to put in a password. I put in my password that the transfer stops. Or I push ok about a file and the transfer stops.
I used the enclosed set up for the 5T so I could use it with windows, which never worked, and I believe my other HD is just journaled. Is that the problem I wonder. Should I set up my 3T like my 5 or does that matter. Thats only a temporary solution I know since i need more space than 3T.

I absolutely have to have this data.

I ran a Diagnostic test on the Pro and it says the battery is needing serviced but nothing about a port or anything.

Should I have the Pro checked out and take a chance the Air might not recognize it or go ahead and buy yet another seagate 5 and try to do a data transfer since it's all taped together anyway?

Or is there another thought someone has for me?

 

[hobowankenobi]

Sorry to hear of the issues.

A lot to unpack, several variables.

Any data you absolutely need to hold onto must be stored in multiple locations. I would start with 3, but more is better. Let's not forget that your data is on a finicky and fragile rotating magnetic disk. Many things can go wrong: mechanical failures, electrical failures, file system failures, physical failures, etc., not to mention user error (deleting/copying over files, etc.)

One drive is never enough; it is playing Russian roulette with your data.

So....first things first: protect data by getting a second copy that you can trust, which means testing (at least spot checking some files) to be sure they open and behave as you expect. I would not do anything to the single copy of data you have until you are sure there is a least one usable second copy.

As for stable and happy external drives, over and about the drive itself, there is formatting, and the bridge board (the USB chip set in the enclosure) that lets the drive be presented to the OS. In a perfect world, one would get a drive, format appropriately for the OS and test it repeatedly before trusting it. Typically we plug and play, and mostly that works. But when it doesn't...not fun.

But, there have been some USB chipsets that simply do not get along well with some Macs. It sucks, but it happens. Could be that. Would explain it working on an older Mac, but not a newer Mac: likely they have different USB chipsets and/or USB firmware that we as users can't change.

It could also be something else like a cable, though that seems unlikely.

So another drive seems like the next step. The hard part is, on the outside chance that the USB bridge in that model Seagate does not play nice with your Mac, does it make sense to get another of the same model? Just something to consider.

Another problem is that file systems that are cross platform (for Windows and Mac, like FAT and exFAT) are less reliable overall than dedicated file systems for each platform, which adds another risk factor to your data.

I just realized....your new Mac is likely booted to APFS file system if the OS is 10.13 or newer, while your older Mac is likely HFS+. That alone could explain the difference. Without getting too technical, suffice to say file systems really matter in a situation like this.

If it were me, I would focus and being sure your data is available and valid on a single machine first, and forgo using multiple Macs for now: Get the data happy on the old Air first.

One other tip once you are ready make another copy: using the Finder to copy that much data at once is fraught with peril. A backup or synchronizing tool is more reliable, and most importantly will give you a report or log of any issues, plus lots of other handy features like comparing for differences, and letting you only move/synchronize what has changed.

 

[Fishrrman]

Since you have a problem "dropping drives", I suggest you get one of these:
https://www.amazon.com/SanDisk-1TB-...r=8-1-fkmr2&keywords=sandisk+extreme+usb3+ssd

You can drop it and it won't break as easily (it's an SSD with no moving parts and it has a rubberized outer body).

Once you have it, use Disk Utility to erase it to "Mac OS extended with journaling enabled".
Now it's ready for data.

Next, I suggest you do this.
Download CarbonCopyCloner:
Download - Carbon Copy Clonerhttps://bombich.com/download
(make sure you get the version for El Capitan).
CCC is FREE to download and use for 30 days.

Now, connect both the Seagate drive that has your data on it AND the new SSD to a Mac. Use a hub if you have to.
Next, open CCC.
Accept the defaults.
Put the source on the left (the Seagate)
Put the target to its right (the SSD)
Let CCC do its thing. This could take a while.

Now you should have a copy of the data on the SSD.

Other things you should know:
I believe Seagate drives come from the factory with special software pre-installed on them that can MESS WITH Mac users.
My advice is to remove it (has to be done with a Seagate app).

As suggested above, you always want MORE THAN ONE COPY of your data.
Three copies are better than just two.