<s>
Repairing	O
disk	O
permissions	O
is	O
a	O
troubleshooting	O
activity	O
commonly	O
associated	O
with	O
the	O
macOS	B-Application
operating	B-General_Concept
system	I-General_Concept
by	O
Apple	O
.	O
</s>
<s>
The	O
BSD	B-Operating_System
layer	O
in	O
macOS	B-Application
is	O
responsible	O
for	O
file-system	O
security	O
,	O
including	O
the	O
management	O
of	O
the	O
Unix	B-Application
(	O
POSIX	O
)	O
permissions	O
model	O
.	O
</s>
<s>
Repairing	O
permissions	O
involves	O
checking	O
the	O
permissions	O
of	O
a	O
set	O
of	O
files	O
and	O
folders	O
on	O
a	O
volume	O
with	O
macOS	B-Application
installed	O
against	O
a	O
list	O
of	O
correct	O
POSIX	O
permissions	O
and	O
correcting	O
any	O
discrepancies	O
.	O
</s>
<s>
Whenever	O
a	O
user	O
installs	O
software	O
that	O
uses	O
the	O
macOS	B-Application
Installer	O
package	O
format	O
,	O
a	O
bill-of-materials	O
file	O
is	O
created	O
which	O
can	O
be	O
consulted	O
for	O
future	O
permission	O
repair	O
.	O
</s>
<s>
Files	O
whose	O
permissions	O
have	O
been	O
incorrectly	O
altered	O
by	O
an	O
administrator	O
,	O
an	O
administrator	O
operating	O
with	O
root	B-Application
privileges	I-Application
,	O
or	O
a	O
poorly	O
designed	O
installer	O
package	O
(	O
installed	O
with	O
similar	O
privileges	O
)	O
can	O
cause	O
a	O
wide	O
array	O
of	O
problems	O
ranging	O
from	O
application	O
errors	O
to	O
the	O
inability	O
to	O
boot	O
macOS	B-Application
.	O
</s>
<s>
Repairing	O
permissions	O
can	O
become	O
necessary	O
,	O
but	O
has	O
become	O
increasingly	O
less	O
so	O
for	O
versions	O
after	O
Panther	B-Operating_System
(	O
10.3	B-Operating_System
)	O
.	O
</s>
<s>
In	O
OS	B-Operating_System
X	I-Operating_System
El	I-Operating_System
Capitan	I-Operating_System
,	O
Apple	O
introduced	O
a	O
security	O
feature	O
called	O
System	B-Operating_System
Integrity	I-Operating_System
Protection	I-Operating_System
.	O
</s>
<s>
With	O
it	O
enabled	O
,	O
root	B-Application
privileges	I-Application
are	O
no	O
longer	O
able	O
to	O
change	O
system	O
files	O
and	O
folders	O
,	O
including	O
their	O
permissions	O
.	O
</s>
<s>
To	O
that	O
end	O
,	O
Disk	B-Application
Utility	I-Application
as	O
well	O
as	O
the	O
corresponding	O
command-line	B-Device
utility	I-Device
lost	O
the	O
ability	O
to	O
repair	B-Operating_System
permissions	I-Operating_System
.	O
</s>
<s>
In	O
systems	O
prior	O
to	O
OS	B-Operating_System
X	I-Operating_System
El	I-Operating_System
Capitan	I-Operating_System
,	O
a	O
permissions	O
repair	O
can	O
be	O
performed	O
by	O
selecting	O
a	O
startup	B-Application
volume	I-Application
and	O
clicking	O
the	O
"	O
Repair	O
Disk	O
Permissions	O
"	O
button	O
in	O
the	O
"	O
First	O
Aid	O
"	O
section	O
of	O
Disk	B-Application
Utility	I-Application
.	O
</s>
<s>
The	O
operation	O
can	O
also	O
be	O
performed	O
by	O
using	O
the	O
command-line	B-Device
utility	I-Device
.	O
</s>
<s>
In	O
El	O
Capitan	O
,	O
the	O
user	O
can	O
instead	O
use	O
two	O
command-line	B-Device
utilities	I-Device
:	O
to	O
repair	O
particular	O
packages	O
or	O
to	O
repair	O
a	O
standard	O
set	O
of	O
system	O
packages	O
.	O
</s>
<s>
In	O
both	O
cases	O
,	O
the	O
user	O
has	O
to	O
disable	O
System	B-Operating_System
Integrity	I-Operating_System
Protection	I-Operating_System
to	O
change	O
permissions	O
of	O
system	O
files	O
and	O
directories	O
.	O
</s>
<s>
In	O
macOS	B-Application
Sierra	O
,	O
is	O
not	O
available	O
.	O
</s>
