external drives readonly mojave

Question

Level 1

11 points

external drives readonly mojave

The read-only external drive issue in Mojave occurs across drive brands and media types. It persists despite suggested remedy steps.

here's my setup:

macbook pro mid-2012 high sierra 10.13.6
macbook pro mid-2015 mojave 10.14.2
WD 4TB 2.5in disc drive - Journaled HFS Plus
Sandisk Ultra Fit 16GB USB key, (Mac OS Extended (Case-sensitive, Journaled) encrypted
WD 1TB hd - My Passport for Mac, (Mac OS Extended (Case-sensitive, Journaled) encrypted

preconditions

all three drives worked read-write on both machines
no sudo usage, just staff
the USB key lived full time on the 2015 mbp. Everyday use included read, write, and execute by staff
the My Passport drive was in infrequent use by both machines

Right after the Mojave upgrade, I noticed the USB key was read-only in the 2015 mbp.

As a test, I plugged the 1TB hd into the Mojave mbp. it was read-only.

postconditions

High Sierra machine can read, write, and execute on the 3 drives
Mojave machine sees all 3 drives as readonly

Remedy steps done on the USB key

Disk Utility repair
Cmd-I, change permissions in dialog to
Ignore permissions in Finder
Reformat as APFS (Case-sensitive, Encrypted)

after each remedy step, i tried to write to the drive on both machines.

i used touch and copying a simple text file.

each worked on High Sierra, failed on Mojave.

i fed a handful of other-brand USB keys to the Mojave machine and saw the readonly issue.

The answers I've seen thus far point to drive format (NTFS, exfat, fat32) or manufacturer-specific issues.

My test case excludes the format possibilities, afaict?

Can others reproduce this issue? I halted plans for Mojave upgrades until a definitive and reproducible solution is found.

MacBook Pro Retina

Posted on Dec 25, 2018 5:36 PM

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Answer 1

Top-ranking reply

Ruleset Author

Level 1

11 points

Jan 5, 2019 9:45 AM in response to Ruleset

Update:

The affected machine was a managed device.

By opening the following, we saw that external hard drives and USB drives were set to readonly by policy

System Information > Software > Profiles

This page describes Media Access configuration Profiles:

https://mosen.github.io/profiledocs/payloads/mediaaccess.html

com.apple.MCX { "mount-controls" = { harddisk-external = "read-only }

@dbeeren answered this in a previous thread:

https://discussions.apple.com/thread/8630289?answerId=34171269022#34171269022

I misread "company" in this reply to mean Apple, rather than "company that administers a macbook".

the problem i suggested is company related. Actually it was't a problem. Since the upgrade 10.14.1 its a company policy that its not allowed to write to an USB drive anymore. Its hardened in a company policy profile.

A helpful support call to Apple solved this.

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Answer 2

Bob-Olga

Level 1

4 points

Jan 1, 2019 7:47 AM in response to Ruleset

I had done a migration from an old iMac to a new iMac with Mohave 10.14.2. All was well for two weeks, then yesterday the thing suddenly would not let me write to two of my four backup drives. Just before that, the computer had crashed and reopened with black screen and a note to wait. After that, the two NTFS drives will not accept files or changes.

Is iBoysoft really a solution. or just another way for someone to make money?

I have four externals:

one NTFS 1TB and one NTFS 2TB for archiving and for compatibility with Windows computers, when needed.

one Mox OS Extended (journaled) for Time Machine backups.

one OS Extended (journaled) for archiving.

The three drives for archiving all have identical files for redundancy - experience has shown that one is not enough, unless I were to want to fill the main hard drive with fill those photos and technical papers.

This foulup has caught me flat-footed and confused by its random occurrence after the two weeks of successful use! I do wish to keep the Windows PC compatibility option open. That has helped us immensely in the past when a Mac "blew a tire" and had to be sidelined for a time.

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