external hard drive now read only after el capitan update

That's what I've done too.

After having to rebuild two macs in two days because of bugs in two separate OSX patch updates, in the trash the mac went.

I can get better reliability from a PC at 1/4 the price.

It's sad to have seen that happen to Apple.

Do a Get Info (command I) on the drive and see if there is an Ignore Ownership box you can check. If that doesn't work, give yourself read/write permissions.

I had the same issues with my Samsung hard drive. It started off as read only & now nothing my macbook doesn't even recognise i have it plugged in? Very annoying.

Same issues with me. I have a Seagate Backup plus for Mac. I copied files to it just one day before upgrading to El Capitan. Now after the update, the drive shows up as "read only" and I am unable to copy anything to it. It is also an NTFS formatted drive. I have the software and drivers from Seagate which enabled me read/write access before. I'm assuming that this may be a Seagate issue, and they need to update things on their end to work with El Capitan. I'm currently awaiting a response from Seagate, unless anyone knows for sure if this is a Mac system issue with the update. Guess there's nothing that can be done in the meantime. Frustrated, for sure!

I have a seagate BUP slim external hard-drive and after updating it was read-only. I tried running first aid using disk utility and didn't work. What I finally had to do is reformat the whole hard-drive and now is writable again. Any reason why is this happening?

Having the exact same problem with a 2TB Seagate Backup Plus.

Have you had any luck fixing the problem or heard back from Seagate at all?

I've tried running the first aid in Disc Utility but it made no difference.

That *****. There has to be a way to fix this. 1.8 TB of movies and music, etc on my external for iTunes. I have zero desire to loose all of that work from ripping my DVDs to iTunes.

I experienced the same problem with Seagate Plus. I have several Macs around and was able to confirm that only those machines where I had updated to El Captain did the permissions change to "read only". When I plug back into units without the upgrade the permissions read correctly. I have not yet found a way to change permissions. Would be grateful if someone can provide a solution. I am thinking that I will simply reformat my drive.

I'd suggest to wait until it has been fixed. Alternatively you could choose to downgrade to Yosemite. Due to the number of issues reported it seems to be clear that there are big issues with almost everything USB. Don't risk to loose your data by doing premature actions now.

It says it's formatted 'Windows NT File System (NTFS)', but it's only ever been used on a macbook pro. it worked just fine yesterday until i upgraded to el capitan.

OS X has never had native write ability on NTFS volumes. You would have had some software or hack to enable writing to NTFS. Whatever you had installed likely is incompatible with El Capitan.

Things you can use: Pargon, Tuxera, NTFS+3G.

However, if you only use it on a Mac, transfer the files off of it, then partition the drive using Disk Utility and set it to GUID Partition Table and Mac OS Extended (Journaled) format. Then, transfer the files back.

For anyone using Seagate drives, I heard back from Seagate tech support and there is new driver software available here:

http://www.seagate.com/in/en/support/external-hard-drives/desktop-hard-drives/ba ckup-plus-desk/ntfs-driver-for-mac-os-master-dl/

After I installed the new Paragon driver - everything works for me now. I have read/write access again.

I discovered Tuxera software on another external Toshiba drive that I had. I installed that and it works. Next goal: Get another 3+TB hard drive to format for OS X and transfer everything over to it. Don't wanna loose the nearly 2 TB I already have on this drive.

This did the trick!