I asked what versions of Excel you were using, but you haven't supplied that
information.

You are doing a length test with a very large number in it. IIRC earlier
versions of Excel didn't allow cells to contain as much text as they do now
(or at least didn't allow VBA to manipulate them), and 2^15 is a very long
string.

I occasionally have trouble with long cells and Excel VBA 2000, where the
VBA can't handle the amount of text that can be placed in the cell. (And
this certainly occurs much earlier than the 32,000 or so characters you're
talking about.)

Which of the parts of the indicated line is the problem? What exactly is
the error?

I can't make a logical explanation if you can't make a logical description
of the problem. :-) You need to supply exact details of what you are
doing.

When you have a line like the one you have flagged, it is not enough to say
"Here is the problem". On what part of the line is the problem? You need
to break out the separate parts and see what it doesn't like. And
especially, you should not be sending the line with both an IF statement and
an assignment statement on it. Break this line out so that the assignment
is on a separate line.

Seeing you are dealing with long strings, you also need to say exactly how
long the one giving problems is. You also need to indicate whether shorter
strings work OK and how long they were.

Regarding your 99.9% question. I doubt that the location of the file is
affecting anything. Excel sometimes gets confused and doesn't provide the
help tips for no apparent reason. On the other hand, your .1% difference
might be causing it.