Frequently Asked Questions
- How come I am not seeing my function show up in the workbook or Function Wizard?
- Most
likely because you didn't load it. If you are running in the debugger, be sure to
specify the full path to the Excel executable on your machine as the
Command
and "$(TargetPath)"
as Command Arguments
in Properties|Configuration
Properties|Debugging
.
- When I open my
.xll
file in Excel nothing happens. - You
need to set macro security to low in order for Excel to register your functions
and macros. For Excel 2003 and earlier, go to
Tools|Options...
and
click on Macro Security...
in the Security
tab. For Excel
2007 and later, from the Office Button click on Excel Options
next
to Exit Excel
on the bottom right. On the Trust Center tab click on
Trust Center Settings...
On the Macro Settings
tab choose
Enable all macros
.
- How do I get my add-in to load every time I start Excel?
-
That is what the Excel
Add-in Manager is for.
- What is up with all those popups showing me errors and warnings?
-
The xll add-in library provides three levels of alerts: error, warning, and information.
Hit Alt-F8 and type
ALERT.FILTER
to control which of these you see.

Your choices are stored in the registry when you hit OK so they persist between
Excel sessions. Hitting Cancel is equivalent to deselecting all alerts.
- Why am I seeing a message box claiming Register failed for: X, where X is the
Excel name of one of my functions?
- You forgot to insert
#pragma XLLEXPORT
as the first line in the body of the corresponding C/C++ function.
- What can I do if
XLL.DOC
is not generating my help file? - Look
in the Debug directory. You should see a folder with the same name as the xll you
are building. In that you will find
.log
files. Look through them in
alphabetical order for error messages.
- Why is
malloc()
failing while trying to allocate large amounts
of memory? - You must compile with default char unsigned.
Properties|C/C++|Command
Line|Additional Options: /J
- How come the last arguments in the constructor of
AddIn
end with
an extra character? - It is a known feature that persists in the Excel 2010
SDK that the last character gets truncated.
- I'm using Vista/Windows 7 and can't veiw the Macrofun.hlp file.
- You
need to install the Windows Help program. Just follow the directions
- When I call my add-in function from Excel it returns
#VALUE
. - This
can occur when there is a mismatch between the C signature you specify in the second
argument to
AddIn
and the true signature.