I appreciated the responses from Gary"s Student, pinmaster, and Gord Dibben.
I tried all the suggestions to no avail (btw, CLEAN/TRIM gave me a 'circular
reference' error message, and I was unable to get the (') added to the lookup
value past the 'error checker').

But I di find that I could get the field recognized by Lookup if I copied
the 'unreadable' column, and did a Paste-Special into a blank column using
the 'Add' option.

I am still unclear what the problem was - Chip Pearson's CellView did not
show any unusual character - but I have a solution :-)

Thanks to all.

Mike

"MichaelRobert" wrote:

I am using LOOKUP in Excel, but it cannot recognize the format of the 'lookup
value' cell which is a 5-digi ZIP code. The data in that cell is imported
from another application, and I cannot determine how it is formatted. As a
result, Lookup returns an 'n/a'.

Everything works fine if I delete the cell contents and enter the same value
manually. I have tried reformatting the cell, moving the data from 'aligned
left' to 'aligned right' with no success. I have also tried setting up an
adjoining column which is the original column multiplied by one, and that
doesn't work.

Maybe if I could see how the cell is formatted, that could give me a lead ...

Any ideas?

Thanks.

Mike