<s>
Outlook	B-Application
Express	I-Application
,	O
formerly	O
known	O
as	O
Microsoft	B-Application
Internet	I-Application
Mail	I-Application
and	I-Application
News	I-Application
,	O
is	O
a	O
discontinued	O
email	B-Protocol
and	O
news	B-Protocol
client	I-Protocol
included	O
with	O
Internet	B-Application
Explorer	I-Application
versions	O
3.0	B-Protocol
through	O
6.0	B-Application
.	O
</s>
<s>
As	O
such	O
,	O
it	O
was	O
bundled	O
with	O
several	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
,	O
from	O
Windows	B-Device
98	I-Device
to	O
Windows	B-Application
Server	I-Application
2003	I-Application
,	O
and	O
was	O
available	O
for	O
Windows	O
3.x	O
,	O
Windows	B-Device
NT	I-Device
3.51	I-Device
,	O
Windows	B-Application
95	I-Application
,	O
Mac	B-Operating_System
System	I-Operating_System
7	I-Operating_System
,	O
Mac	B-Operating_System
OS	I-Operating_System
8	I-Operating_System
,	O
and	O
Mac	B-Operating_System
OS	I-Operating_System
9	I-Operating_System
.	O
</s>
<s>
In	O
Windows	B-Application
Vista	I-Application
,	O
Outlook	B-Application
Express	I-Application
was	O
superseded	O
by	O
Windows	B-Protocol
Mail	I-Protocol
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
is	O
a	O
different	O
application	O
from	O
Microsoft	B-Application
Outlook	I-Application
.	O
</s>
<s>
The	O
similar	O
names	O
lead	O
many	O
people	O
to	O
conclude	O
incorrectly	O
that	O
Outlook	B-Application
Express	I-Application
is	O
a	O
stripped-down	O
version	O
of	O
Microsoft	B-Application
Outlook	I-Application
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
uses	O
the	O
Windows	O
Address	O
Book	O
to	O
store	O
contact	O
information	O
and	O
integrates	O
tightly	O
with	O
it	O
.	O
</s>
<s>
Windows	B-Application
XP	I-Application
,	O
also	O
integrates	O
with	O
Windows	B-Application
Messenger	I-Application
.	O
</s>
<s>
Version	O
1.0	O
was	O
released	O
as	O
Microsoft	B-Application
Internet	I-Application
Mail	I-Application
and	I-Application
News	I-Application
in	O
1996	O
following	O
the	O
Internet	B-Protocol
Explorer	I-Protocol
3	I-Protocol
release	O
.	O
</s>
<s>
This	O
add-on	O
precedes	O
the	O
Internet	O
Mail	O
profile	O
for	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
4.0	O
bundled	O
in	O
Windows	B-Application
95	I-Application
.	O
</s>
<s>
Internet	B-Application
Mail	I-Application
and	I-Application
News	I-Application
handled	O
only	O
plain	O
text	O
and	O
rich	O
text	O
(	O
RTF	O
)	O
email	B-Protocol
,	O
lacking	O
HTML	O
email	B-Protocol
.	O
</s>
<s>
In	O
1997	O
the	O
program	O
was	O
changed	O
and	O
renamed	O
to	O
Outlook	B-Application
Express	I-Application
and	O
bundled	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
4	I-Protocol
.	O
</s>
<s>
The	O
Windows	O
executable	O
file	O
for	O
Outlook	B-Application
Express	I-Application
,	O
msimn.exe	B-Application
,	O
is	O
a	O
holdover	O
from	O
the	O
Internet	B-Application
Mail	I-Application
and	I-Application
News	I-Application
era	O
.	O
</s>
<s>
Like	O
Internet	B-Application
Explorer	I-Application
,	O
Outlook	B-Application
Express	I-Application
4	O
can	O
run	O
on	O
Mac	B-Operating_System
System	I-Operating_System
7	I-Operating_System
,	O
OS	O
8	O
,	O
and	O
OS	B-Operating_System
9	I-Operating_System
.	O
</s>
<s>
At	O
one	O
point	O
,	O
in	O
a	O
later	O
beta	O
version	O
of	O
Outlook	B-Application
Express	I-Application
5	O
,	O
Outlook	B-Application
Express	I-Application
contained	O
a	O
sophisticated	O
and	O
adaptive	O
spam	O
filtering	O
system	O
;	O
however	O
this	O
feature	O
was	O
removed	O
shortly	O
before	O
launch	O
.	O
</s>
<s>
Nearly	O
two	O
years	O
later	O
,	O
a	O
similar	O
system	O
,	O
using	O
a	O
similar	O
method	O
of	O
adaptive	O
filtering	O
,	O
appeared	O
as	O
a	O
feature	O
of	O
Microsoft	B-Application
Outlook	I-Application
.	O
</s>
<s>
Internet	B-Protocol
Explorer	I-Protocol
5	I-Protocol
required	O
Outlook	B-Application
Express	I-Application
5	O
to	O
save	O
Web	O
Archive	O
files	O
(	O
see	O
MHTML	B-Application
)	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
6	O
is	O
the	O
last	O
version	O
of	O
the	O
software	O
with	O
Outlook	O
branding	O
.	O
</s>
<s>
It	O
has	O
a	O
similar	O
layout	O
to	O
Outlook	B-Application
Express	I-Application
5	O
.	O
</s>
<s>
It	O
was	O
included	O
with	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
Microsoft	B-Application
Internet	I-Application
Mail	I-Application
and	I-Application
News	I-Application
1.0	O
was	O
released	O
in	O
1996	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
3	I-Protocol
.	O
</s>
<s>
Microsoft	B-Application
Internet	I-Application
Mail	I-Application
and	I-Application
News	I-Application
2.0	O
was	O
released	O
later	O
in	O
1996	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
4.0	O
,	O
which	O
was	O
included	O
in	O
Windows	B-Device
98	I-Device
(	O
June	O
1998	O
)	O
and	O
integrated	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
4	I-Protocol
,	O
stored	O
messages	O
in	O
*	O
.mbx	O
files	O
(	O
similar	O
to	O
the	O
Mbox	B-Application
format	O
used	O
in	O
Unix-based	O
systems	O
)	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
5.0	O
,	O
which	O
was	O
included	O
in	O
Windows	B-Device
98	I-Device
Second	O
Edition	O
(	O
SE	O
)	O
(	O
June	O
1999	O
)	O
and	O
integrated	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
5	I-Protocol
,	O
switched	O
to	O
*	O
.dbx	O
files	O
,	O
with	O
a	O
separate	O
file	O
for	O
each	O
mailbox	O
folder	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
5.01	O
was	O
included	O
in	O
Windows	B-Application
2000	I-Application
(	O
February	O
2000	O
)	O
and	O
integrated	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
5.01	I-Protocol
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
5.5	O
was	O
included	O
in	O
Windows	B-Device
Me	I-Device
(	O
June	O
2000	O
)	O
and	O
integrated	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
5.5	I-Protocol
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
6.0	B-Application
was	O
included	O
in	O
Windows	B-Application
XP	I-Application
(	O
October	O
2001	O
)	O
and	O
integrated	O
with	O
Internet	B-Application
Explorer	I-Application
6	I-Application
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
4.0	O
was	O
included	O
in	O
Microsoft	B-Application
Office	I-Application
98	I-Application
Macintosh	I-Application
Edition	I-Application
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
5.01	O
was	O
integrated	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
5	I-Protocol
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
5.01	O
was	O
bundled	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
5.01	I-Protocol
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
5.5	O
was	O
bundled	O
with	O
Internet	B-Protocol
Explorer	I-Protocol
5.5	I-Protocol
.	O
</s>
<s>
Builds	O
of	O
"	O
Outlook	B-Application
Express	I-Application
7	O
"	O
appeared	O
in	O
early	O
builds	O
of	O
Windows	B-Application
Vista	I-Application
when	O
in	O
development	O
as	O
"	O
Longhorn	O
"	O
.	O
</s>
<s>
It	O
relied	O
on	O
WinFS	B-Application
for	O
the	O
management	O
and	O
storage	O
of	O
contacts	O
and	O
other	O
data	O
.	O
</s>
<s>
The	O
final	O
version	O
of	O
Vista	B-Application
included	O
a	O
successor	O
to	O
Outlook	B-Application
Express	I-Application
known	O
as	O
Windows	B-Protocol
Mail	I-Protocol
(	O
Vista	B-Application
)	O
.	O
</s>
<s>
Beginning	O
with	O
the	O
text-based	O
Unix	B-Protocol
Mail	I-Protocol
command	I-Protocol
,	O
email	B-Protocol
traditionally	O
used	O
the	O
inline	O
or	O
bottom	O
posting	O
styles	O
when	O
replying	O
to	O
messages	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
,	O
as	O
well	O
as	O
Lotus	B-Operating_System
Notes	I-Operating_System
and	O
Microsoft	B-Application
Outlook	I-Application
,	O
top-post	O
(	O
show	O
replies	O
newest	O
to	O
oldest	O
)	O
by	O
default	O
.	O
</s>
<s>
Microsoft	B-Application
Outlook	I-Application
and	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
use	O
a	O
proprietary	B-Application
email	B-Protocol
attachment	O
format	O
called	O
Transport	O
Neutral	O
Encapsulation	O
Format	O
(	O
TNEF	O
)	O
to	O
handle	O
formatting	O
and	O
other	O
features	O
specific	O
to	O
Outlook	O
such	O
as	O
meeting	O
requests	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
and	O
other	O
email	B-Protocol
clients	I-Protocol
are	O
unable	O
to	O
read	O
this	O
format	O
.	O
</s>
<s>
This	O
can	O
be	O
confusing	O
to	O
Outlook	B-Application
Express	I-Application
users	O
(	O
as	O
well	O
as	O
those	O
who	O
use	O
other	O
email	B-Protocol
clients	I-Protocol
)	O
who	O
receive	O
attachments	O
sent	O
from	O
Outlook	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
has	O
been	O
prone	O
to	O
a	O
number	O
of	O
problems	O
which	O
can	O
corrupt	O
its	O
files	O
database	O
,	O
especially	O
when	O
the	O
database	O
increases	O
in	O
size	O
due	O
to	O
an	O
increasing	O
number	O
of	O
stored	O
emails	O
and	O
during	O
database	O
compaction	O
.	O
</s>
<s>
Microsoft	O
has	O
also	O
released	O
documentation	O
which	O
may	O
be	O
able	O
to	O
correct	O
some	O
non-severe	O
problems	O
and	O
restore	O
access	O
to	O
email	B-Protocol
messages	O
,	O
without	O
resorting	O
to	O
third-party	O
solutions	O
.	O
</s>
<s>
However	O
,	O
with	O
the	O
latest	O
updates	O
applied	O
,	O
Outlook	B-Application
Express	I-Application
now	O
makes	O
backup	O
copies	O
of	O
DBX	O
files	O
prior	O
to	O
compaction	O
.	O
</s>
<s>
They	O
are	O
stored	O
in	O
the	O
Recycle	B-Application
Bin	I-Application
.	O
</s>
<s>
If	O
an	O
error	O
occurs	O
during	O
compaction	O
and	O
messages	O
are	O
lost	O
,	O
the	O
DBX	O
files	O
can	O
be	O
copied	O
from	O
the	O
recycle	B-Application
bin	I-Application
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
was	O
one	O
of	O
the	O
earlier	O
email	B-Protocol
clients	I-Protocol
to	O
support	O
HTML	O
email	B-Protocol
and	O
scripts	O
.	O
</s>
<s>
Previously	O
,	O
another	O
security	O
flaw	O
was	O
that	O
a	O
script	B-Language
could	O
automatically	O
be	O
opened	O
as	O
an	O
attachment	O
.	O
</s>
<s>
Another	O
bug	O
was	O
in	O
Outlook	B-Application
Express	I-Application
's	O
attachment	O
handling	O
that	O
allowed	O
an	O
executable	O
to	O
appear	O
to	O
be	O
a	O
harmless	O
attachment	O
such	O
as	O
a	O
graphics	O
file	O
.	O
</s>
<s>
Opening	O
or	O
previewing	O
the	O
email	B-Protocol
could	O
cause	O
code	O
to	O
run	O
without	O
the	O
user	O
's	O
knowledge	O
or	O
consent	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
uses	O
Internet	B-Application
Explorer	I-Application
to	O
render	O
HTML	O
email	B-Protocol
.	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
has	O
been	O
subjected	O
to	O
many	O
security	O
vulnerabilities	O
and	O
concerns	O
.	O
</s>
<s>
With	O
Outlook	B-Application
Express	I-Application
SP2	O
(	O
part	O
of	O
Windows	B-Application
XP	I-Application
SP2	O
)	O
,	O
Microsoft	O
has	O
tried	O
to	O
correct	O
the	O
security	O
holes	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
now	O
blocks	O
images	O
inside	O
emails	O
by	O
default	O
.	O
</s>
<s>
It	O
uses	O
only	O
the	O
restricted	O
security	O
zone	O
for	O
HTML	O
email	B-Protocol
,	O
which	O
disables	O
scripts	O
and	O
imposes	O
restrictions	O
on	O
what	O
web	O
content	O
can	O
be	O
rendered	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
does	O
not	O
correctly	O
handle	O
MIME	B-Protocol
,	O
and	O
will	O
not	O
display	O
the	O
body	O
of	O
signed	O
messages	O
inline	O
.	O
</s>
<s>
Users	O
get	O
a	O
filled	O
email	B-Protocol
and	O
one	O
attachment	O
(	O
one	O
of	O
the	O
message	O
text	O
and	O
one	O
of	O
the	O
signature	O
)	O
and	O
therefore	O
need	O
to	O
open	O
an	O
attachment	O
to	O
see	O
the	O
email	B-Protocol
.	O
</s>
<s>
If	O
the	O
email	B-Protocol
has	O
been	O
forwarded	O
several	O
times	O
,	O
users	O
need	O
to	O
open	O
attached	O
email	B-Protocol
messages	O
one	O
inside	O
the	O
other	O
multiple	O
times	O
to	O
reach	O
the	O
parent	O
email	B-Protocol
message	O
.	O
</s>
<s>
When	O
replying	O
or	O
forwarding	O
a	O
message	O
to	O
a	O
user	O
who	O
has	O
a	O
digital	O
signature	O
,	O
Outlook	B-Application
Express	I-Application
gives	O
an	O
error	O
and	O
does	O
not	O
allow	O
the	O
user	O
to	O
continue	O
if	O
there	O
is	O
no	O
digital	O
signature	O
installed	O
for	O
the	O
sender	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
does	O
not	O
have	O
a	O
documented	O
object	B-Application
model	I-Application
like	O
Microsoft	B-Application
Outlook	I-Application
.	O
</s>
<s>
Programmatic	O
access	O
to	O
,	O
or	O
control	O
of	O
Outlook	B-Application
Express	I-Application
for	O
custom	O
messaging	O
applications	O
or	O
plugins	O
is	O
not	O
officially	O
documented	O
or	O
supported	O
by	O
Microsoft	O
.	O
</s>
<s>
A	O
significant	O
one	O
was	O
the	O
PGP	B-Application
plugin	O
because	O
it	O
was	O
the	O
only	O
example	O
of	O
a	O
working	O
plugin	O
whose	O
source	O
code	O
was	O
available	O
(	O
licensed	O
under	O
GPL	B-License
)	O
.	O
</s>
<s>
Outlook	B-Application
Express	I-Application
does	O
not	O
have	O
a	O
dedicated	O
spell	O
checker	O
.	O
</s>
<s>
It	O
can	O
use	O
the	O
spell	O
checkers	O
from	O
Microsoft	B-Application
Office	I-Application
if	O
Office	O
is	O
also	O
installed	O
.	O
</s>
<s>
However	O
,	O
the	O
Office	B-Application
2007	I-Application
spell	O
checkers	O
,	O
except	O
for	O
the	O
French	O
spell	O
checker	O
,	O
are	O
incompatible	O
with	O
Outlook	B-Application
Express	I-Application
.	O
</s>
<s>
A	O
solution	O
is	O
to	O
install	O
any	O
pre-Office	O
2007	O
proofing	O
tools	O
or	O
use	O
a	O
third	O
party	O
spell-checking	O
app	O
for	O
Outlook	B-Application
Express	I-Application
.	O
</s>
<s>
Windows	B-Application
Live	I-Application
Mail	I-Application
,	O
which	O
is	O
based	O
on	O
Windows	B-Protocol
Mail	I-Protocol
's	O
source	O
code	O
,	O
contains	O
built-in	O
spell	O
checking	O
support	O
(	O
now	O
for	O
US	O
English	O
and	O
numerous	O
other	O
languages	O
)	O
and	O
is	O
freely	O
downloadable	O
for	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
Cancelling	O
sending	O
an	O
email	B-Protocol
while	O
it	O
is	O
being	O
sent	O
does	O
not	O
effectively	O
prevent	O
it	O
from	O
being	O
sent	O
.	O
</s>
<s>
Similarly	O
,	O
when	O
importing	O
.PST	B-Operating_System
files	O
,	O
cancelling	O
the	O
import	O
while	O
it	O
is	O
in	O
progress	O
merely	O
cancels	O
the	O
import	O
of	O
the	O
current	O
folder	O
and	O
the	O
import	O
resumes	O
with	O
the	O
next	O
folder	O
.	O
</s>
<s>
Furthermore	O
,	O
Outlook	B-Application
Express	I-Application
only	O
supports	O
.dbx	O
files	O
that	O
are	O
smaller	O
than	O
2	O
GB	O
,	O
and	O
may	O
have	O
performance	O
problems	O
when	O
dealing	O
with	O
files	O
approaching	O
that	O
limit	O
.	O
</s>
