All flash-drives and HDs were change to read-only after installing Sierra 10.12.4

I am running a MacMini (late 2014) on jusst updated Sierra 10.12.4.


After update, some apps started to miss-behave. Discovered that disks (cmd-I) were all read only. After a lot of reading, I tried starting up in cmd-S and cmd-R. At the terminal, I tried chown root and chmod 775 (and 1775 for main) but all were refused operations for read-only volumes even in admin. Running terminal from the desktop yields to the same result. After many tries, the system went wild and would not boot even in safe mode. I reloaded a new copy of the OS from the recovery mode.


I got the main drive back and at cmd-I it shows a lock icon and the sharing and permissions settings correctly. I set those and the volume is fine, minus the contents of a large directory (another story). However the secondary HD (USB) and the flash-drive didn't budge. Not only that are read-only, in cmd-I they do not show a lock icon or a way to change the permissions. I have exhausted my repetoire and would welcome some brain power on this problem.


Any help is welcomed. Thanks in advance.

Mac mini, macOS Sierra (10.12.4)
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mrx5 wrote:


Thx Barney-15E:


I upgraded from the previous release as I keep updates fairly close to the latest.

The drives are both NTFS because of the PC where they originated. I wasn't careful enough to reformat it then but it has worked without problems for nearly 3 years in read, write and delete operations. I never used thrid party windows drivers.

While there is a trick to make the OS write (albeit haphazardly) to NTFS, I would imagine you would remember using it.

There is no other native writing ability in OS X/macOS. You would have either ran the terminal commands to enable mounting the volumes as writeable (it also has to be done on a per-drive basis, so you would have had to do it with every drive), or you installed the software that came with one of the drives.

That software would have included a crippled version of either Tuxera or Paragon.

It is quite common that those drivers will fail to work correctly with a new OS.

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