I had a theory. It did not pan out in my experiments. But my situation is
probably very different from yours, so it might be worth pursuing, if you
think it might be applicable.

Do the workbooks that exhibit the problem have links to other workbooks?

If they do, I wonder how they behave under each of the following conditions:
(a) the link target has a new file name (i.e. the link no longer points to
an Excel workbook); (b) the link target is currently open writable (i.e. not
read-only) by another user; and (c) the link target cells no longer have
valid values for XIRR or EDATE.

None of these presents a challenge in my environment; Excel is well-behaved.
But I have WinXP and Excel 2003; you have Excel 2007 and perhaps Vista.
Also, you might be using a different type of file system.

If that does not pan out, look for factors that might be common among the
workbooks that exhibit problems. Often, the perception of "intermittent"
behavior boils down to a specific set of conditions that cause a very
reproducible behavior, once it is understood.

When you finally isolate the problem, I hope you will post an update to this
thread.


---- original message -----

"Wibbs" wrote in message
...
Workbooks were originally written in 2003 and are on a network - users
work
via TS. Currently in middle of migration, so some users are opening in
2007
as a 2003 compatible file. Seems to be an intermittent problem, sometimes
the XIRR and EDATE functions seem to be OK, othertimes they are replaced
by
#N/A.

It is not the case that formula refers to a cell that uses the NA()
function or to a UDF that returns the xlErrNA value.

Currently using Service Pack 1 and operating via Terminal Services.

Thanks
"JoeU2004" wrote:

"Wibbs" wrote:
XIRR and EDATE functions are sometimes changed to #NA in 2007
when saved in compatability mode.

Please clarify the problem statement.

First, do you mean that the problem is seen when the workbook is opened
in
Excel 2007? Or do you mean when it is opened in Excel 2003?

Also, is it opened on the same computer, or on a different computer? Is
the
file on a shared disk and opened over the network?

Second, do you mean the #N/A error or the #NAME? error?

The #NAME? error suggests that the ATP has not been enabled ("loaded").
Note that the ATP can be installed, but not enabled. See Tools Add-Ins
in
Excel 2003.

The #N/A error indicates that a formula refers to a cell that uses the
NA()
function or to a UDF that returns the xlErrNA value. Since these are
programmable errors, you need to look at the worksheet and macro designs
to
understand the conditions when these errors are returned. The Evaluate
Formula feature might help. See Tools Formula Auditing in Excel 2003.


----- original message -----

"Wibbs" wrote in message
...
XIRR and EDATE functions are sometimes changed to #NA in 2007 when
saved
in
compatability mode. This does not happen everytime, but has happened
to a
number of spreadsheets. These provide crucial information to the
company
and
would like to know how to fix this.