MetaStock -> Tools -> Indicator Builder -> New
Copy and paste formula below.


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Missing trade days
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{Plots missing daily (weekday) bars count - v2.0

©Copyright 2003-2011 Jose Silva
http://www.metastocktools.com }

{User input}
ChkVol:=Input("Count zero-vol bars as no-trade days? [1]Yes [0]No",0,1,1);
VolMissing:=If(ChkVol,V=0,0);

{Calendar WeekDay counter}
y:=Year()-(Month()<3);
leap:=Int(y/4)-Int(y/100)+Int(y/400);
mth:=Int((2+153*(Month()-3+12*(Month()<3)))/5);
dayNr:=DayOfMonth()+mth+y*365+leap-30425;
WkDayCount:=
 Int((DayNr+3)/7)+   {Mon}
 Int((DayNr+2)/7)+   {Tue}
 Int((DayNr+1)/7)+   {Wed}
 Int((DayNr)/7)+     {Thu}
 Int((DayNr-1)/7);   {Fri}

{Missing days count}
missCount:=WkDayCount-ValueWhen(2,1,WkDayCount)
-1+VolMissing;

{Plot in own window below chart}
missCount

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