Thanks, Michaelene! The files that are exported are not more than 5MB, but can have a max of 95 columns (layouts usually are less as users don't need all the columns when they export to Excel, only the layout they are in), and up to 10,000 lines. The issue is usually seen when filters are applied - when no filters are applied, the error doesn't occur.
Thanks for any info!
#ApptioPlanning(ITP/ITFMF)