What happens if you enter a new date into one of the cells? Or type over one
of the serial numbers with a date? Does the format change, or does it still
display a serial number?

If the new entry displays properly, then try this. Enter a 1 into any blank
cell. Copy that cell. Select your existing data. From the Edit Menu,
select "Paste Special". Click the "Values" and "Multiply" options. Click OK.

If that still doesn't help, then I'm not sure what else to suggest. Perhaps
more info on the VB code you're working on may lead to a clue?

HTH,
Elkar


"Kamran" wrote:

Unfortunately that's not it. All the dates in all locations on the sheet
changed at once, and I made no format changes. They are all currently set
for mm/dd/yyyy, but they all display in serial number anyway. And then
there's the decimal display issue. I've never seen anything like this happen
all at once. I even tried disabling the VB module that I was working when
the problem started, but that didn't change anything.