How reset margins in Excel workbook?
 

merged data with varying number of columns, reset page size to permit highest
number of columns but margins do not recognize pages with these large number
of columns, i.e., drops last 5 columns.

Maybe it's the print range that's the trouble.

File|Print Area
(set it to what you want--or clear it and let excel guess)

KYgirl wrote:

merged data with varying number of columns, reset page size to permit highest
number of columns but margins do not recognize pages with these large number
of columns, i.e., drops last 5 columns.

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Dave Peterson