<s>
A	O
Microsoft	B-Application
Reserved	I-Application
Partition	I-Application
(	O
MSR	O
)	O
is	O
a	O
partition	B-Application
of	O
a	O
data	B-General_Concept
storage	I-General_Concept
device	I-General_Concept
,	O
which	O
is	O
created	O
to	O
reserve	O
a	O
portion	O
of	O
disk	O
space	O
for	O
possible	O
subsequent	O
use	O
by	O
a	O
Windows	B-Application
operating	I-Application
system	I-Application
installed	O
on	O
a	O
separate	O
partition	B-Application
.	O
</s>
<s>
No	O
meaningful	O
data	O
is	O
stored	O
within	O
the	O
MSR	O
;	O
though	O
from	O
the	O
MSR	O
,	O
chunks	O
may	O
be	O
taken	O
for	O
the	O
creation	O
of	O
new	O
partitions	B-Application
,	O
which	O
themselves	O
may	O
contain	O
data	O
structures	O
.	O
</s>
<s>
The	O
GUID	B-Application
Partition	I-Application
Table	I-Application
(	O
GPT	O
)	O
label	O
for	O
this	O
partition	B-Application
type	O
is	O
E3C9E316-0B5C-4DB8-817D-F92DF00215AE	O
.	O
</s>
<s>
Formerly	O
,	O
on	O
disks	O
formatted	O
using	O
the	O
master	B-Device
boot	I-Device
record	I-Device
(	O
MBR	O
)	O
partition	B-Application
layout	O
,	O
certain	O
software	O
components	O
used	O
hidden	O
sectors	O
of	O
the	O
disk	O
for	O
data	B-General_Concept
storage	I-General_Concept
purposes	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
Logical	O
Disk	O
Manager	O
(	O
LDM	O
)	O
,	O
on	O
dynamic	O
disks	O
,	O
stores	O
metadata	O
in	O
a	O
1MB	O
area	O
at	O
the	O
end	O
of	O
the	O
disk	O
which	O
is	O
not	O
allocated	O
to	O
any	O
partition	B-Application
.	O
</s>
<s>
The	O
UEFI	B-Architecture
specification	O
does	O
not	O
allow	O
hidden	O
sectors	O
on	O
GPT-formatted	O
disks	O
.	O
</s>
<s>
Microsoft	O
reserves	O
a	O
chunk	O
of	O
disk	O
space	O
using	O
this	O
MSR	O
partition	B-Application
type	O
,	O
to	O
provide	O
an	O
alternative	O
data	B-General_Concept
storage	I-General_Concept
space	O
for	O
such	O
software	O
components	O
which	O
previously	O
may	O
have	O
used	O
hidden	O
sectors	O
on	O
MBR	O
formatted	O
disks	O
.	O
</s>
<s>
Small	O
software-component-specific	O
partitions	B-Application
can	O
be	O
allocated	O
from	O
a	O
portion	O
of	O
the	O
space	O
reserved	O
in	O
the	O
MSR	O
partition	B-Application
.	O
</s>
<s>
Beginning	O
in	O
Windows	B-Application
10	O
,	O
the	O
minimum	O
size	O
of	O
the	O
MSR	O
is	O
16MB	O
which	O
the	O
installer	O
allocates	O
by	O
default	O
.	O
</s>
<s>
The	O
MSR	O
should	O
be	O
located	O
after	O
the	O
EFI	B-Device
System	I-Device
Partition	I-Device
(	O
ESP	O
)	O
and	O
any	O
OEM	O
service	O
partitions	B-Application
,	O
but	O
it	O
must	O
be	O
located	O
before	O
any	O
primary	O
partitions	B-Application
of	O
bootable	B-Operating_System
Windows	B-Application
operating	I-Application
systems	I-Application
.	O
</s>
<s>
Microsoft	O
expects	O
an	O
MSR	O
to	O
be	O
present	O
on	O
every	O
GPT	B-Application
disk	I-Application
,	O
and	O
recommends	O
it	O
to	O
be	O
created	O
as	O
the	O
disk	O
is	O
initially	O
partitioned	O
.	O
</s>
