Seagate External HDD won't show up.

I have tried another cable. It does not show up in the system profiler. The light goes on and it feels like the drive is spinning when I hold the case.

Your symptoms could be an indication that the drive died when you tried to erase it.

A drive that cannot tell Disk Utility its Make&Model, and a sensible, non-zero size/capacity, has died.

The most frequent cause of death of external drives is the converter-card in the enclosure. If a standard drive was used, the drive can be sometimes be removed and placed in a new enclosure, and may be fine.

But some manufacturers combine the adapter card onto the drive card, and death of that card cannot be fixed.

Thank you for this excellent information. I imagine that along with low prices we have to expect less than excellent reliability. It teaches me that 2 back ups is not redundant.

Happy New Year to you and all the people who generously share their knowledge.

Since it does not show up in System Profiler that tends to indicate the enclosure failed. Likely the disk inside is still good.

Yes, I can tell the drive is spinning. I'm not sure what you mean by 'enclosure' or 'card'. I need to educate myself on what's inside these.

An external USB enclosure includes electronics to convert the USB signal to the HD's SATA signal. If only the HD itself was bad System Profiler would show the enclosure electronics and might show something but not all information about the disk..

If the electrons really failed then system profiler will not show anything

I'm having the same trouble - since I upgraded to El Capitan, I've had to use the NTFS Paragon install so that I could actually copy files across to my Seagate 500GB External hard drive.

Today I tried to copy a folder of images across and it was back to 'read-only'. I updated the NTFS and restarted the computer and since then the drive won't show in my finder - it's also now saying I've used up the full 500GB when I was nowhere near the capacity? Showing up in Disk Utility and in System Report (see below)

I have also had to update the Seagate Dashboard - where the device is recognised, and again is saying it is full?! I can't view the files or access them to see what's taking up so much room?! I hope I haven't lost everything?!

Any help would be greatly appreciated - it wad showing up fine earlier on today - but as a 'read-only'. I only have PC's in the house and have plugged it into one of those - all my files are on it and I have 379GB free?

Thanks

I had updated to el Capitan long before I had any problem. Talking to friends, I'm learning external HD failures are more common than I had thought. THe only answer is, I think, cloud backup and/or redundancy.

As soon as I can get this sorted I'm going old school and backing everything up to an actual disc that you eject and write on 😁 at least I haven't lost anything because it's still all on there - I just can't see it or edit it!!!

since I upgraded to El Capitan...

ElCapitan has a new requirement for add-ons that include extensions. They MUST be properly signed by the developer, or they simply do not get loaded.

Check with Paragon to be sure they certify that their utility and driver are ELCapitan compatible. Many are not, and it has been a rude shock.

Really!! Gosh. That is dismaying news.

Could this happen all of a sudden due to my upgrading it? That's the only thing I have done differently. If not - is there a way to get my files off my hard drive onto a compatible version, or is it a case of buying the full programme... SeaGate say I only need this particular one - Paragon NTFS for Mac OS X -because I only have the SeaGate device so don't need to full package - this is the bit I upgraded today. I've seen this a LOT since ElCapitan launched. There is nothing wrong with the device, I've only had it a few months and hardly put anything on there - but what is on there IS MY BACK UP as I was trying to clear room off my Mac - so can't wipe it! Why is this so hard?! Plug a device in, save your files et voila... instead of downloading add on after add on to get it to work!

I don't have the full version - this is on their site - but I don't want to buy it yet in case this isn't what I need? Sorry I have absolutely no idea about this stuff...?! If I buy this package - will my SeaGate device work?

https://www.paragon-software.com/home/ntfs-mac/index.html

If you had asked here earlier, readers would have suggested you use Ex-FAT for Mac and PC compatibility, or GUID with MAC OS Extended format for Mac-only use. Changing formats now does require you to erase the drive, which you said you do not want to do.

The Mac can Read, but not Write, Windows New Technology File System (NTFS) drives. Utilities such as paragon NTFS add that capability by installing an Extension.

ElCapitan adds a new requirement that those Extensions be properly signed with an Apple developer certificate, so many older versions of things with Extensions stopped working when ElCapitan came out.

That does appear to be "the right stuff" to buy to get your drive talking NTFS in ElCapitan.