Permissions on external HD / not writable

Question

Permissions on external HD / not writable

Hello, I have a Seagate external 4TB hard drive about a year old, APFS formatted as a single volume and I'm running a 20178 27" Retina 5K 3.5 GHz i5 processor 24GB RAM iMac and High Sierra 10.13.6

I use this as storage for photography and almost exclusively either copy files to it or access it with Lightroom. Lately Lightroom has been saying it can't open the catalog because it doesn't have permission to write to the disk, but:

• Disk info says my account has permission to Read/Write to the drive.

• First Aid says the disk is ok but gives a few warnings about object Unable to mark physical extent range allocated for space verification. Googling that sounded like it might be an issue, but not immediately major and not causing my write issues.

• Disk Utility, in the Info screen screen for the drive, says the disk is not writeable.

• I have been able to fix this in the past, I don't recall exactly how, I thought it might have been by repairing permissions, but I see that's not an option in either Disk Utility or Onyx which I also use, although rarely since I upgraded to High Sierra.

• The other strange thing about the disk is that it will not auto mount on reboot, I have to mount it through Disk Utility - that has been happening since day 1 and I assumed a High Sierra glitch, drive size issue, or APFS formatting quirk.

**ok, this is weird - I just went to get disk info and where my account name should be coming up it says "Fetching..."

Any thoughts? Thanks!

MacBook Pro, OS X Yosemite (10.10.3), null

Posted on Sep 24, 2018 5:04 PM

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Answer 1

Best reply

todfromishpeming Author

Level 1

9 points

Sep 28, 2018 11:42 AM in response to Barney-15E

Well, if anyone else stumbles across this, more research has shown that's it's a pretty prevalent problem, mostly occurring on NTFS formatted drives. That reminded me that when I first started using this system I had a large, external NTFS drive I was using and had an app/extension the loaded that let me write to it (what with Apple and NTFS not playing well together) and when I retired that drive I got rid of the extension. I started poking around online and saw that Seagate has a piece of software you can download and one of the things it does is give access to NTFS drives so I installed it. After a reboot I was able to use the drive again - and the drive mounted automatically. Why that works I couldn't say since it's APFS and not NTFS, it doesn't make sense. I did run a lot of variations of things in the Terminal but none of them seemed to work so I don't want to attribute the fix to that.

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Answer 2

Barney-15E

Level 10

112,776 points

Sep 24, 2018 5:53 PM in response to todfromishpeming

Do you need permissions on that drive? I.e., do you need to protect areas from other users?

If not, check the box to ignore ownership.

You are not looking at the permission for the drive, though. You are looking at the permissions for the root level of the volume.

Fetching is what shows when there is a conflict in the UID of the user chosen. I don't know how to fix it.

System:wheel are the normal user:group for the root level of a hard drive. However, you should be able to change it to whatever you want (on a non-startup drive). However, yours looks like it is preventing that.

Using APFS on a spinning hard drive is not recommended and certainly does not provide any benefit over HFS+.

I don't see anything else that would indicate a problem. However, it does seem something is amiss.

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Answer 3

Sep 25, 2018 10:11 AM in response to Barney-15E

I got interrupted last night. To answer the rest of your questions - no, I don't need permissions on that drive, I will try checking the box to ignore ownership and see what happens, it seems like a workaround to the problem and not a solution but at this point I'll take it if it works.

And thanks for explaining what Fetching and System:wheel are.

If I didn't have so much data on the drive already I'd reformat it, but I don't have anywhere to dump 3 TB for temp storage.

Thanks!

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Answer 4

Barney-15E

Level 10

112,776 points

Sep 25, 2018 5:00 PM in response to todfromishpeming

Not a seagate.

That's been my feeling for quite some time, now.

I'm trying some Toshiba's, but I don't think I've had them long enough to make a definite conclusion. They have already lasted longer than any Seagate I've owned.

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Answer 5

Barney-15E

Level 10

112,776 points

Sep 28, 2018 1:32 PM in response to todfromishpeming

That happens on NTFS because it is a proprietary Microsoft file system. MacOS can only read from it natively. You have to install third-party software to write to it

The drive manufacturers trick you into installing their crapware so that you can write to their drive instead of just telling customers to reformat the drive.

The software is crap and will usually break when the OS is updated

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