Microsoft Excel Slow To Open - Load Faster [Tutorial]. When your Microsoft Excel spreadsheet slows to a crawl, you can’t help but notice. It may take longer to open and save your files, longer for Excel to calculate your formulas, and longer for the screen to refresh after entering data, or sorting and formatting the cells. System memory is the other issue that relates to Excel’s slowness. Slow spreadsheets take longer to manage and, as always, time is money. We’ll show you how to tackle this problem. This tutorial will apply for computers, laptops, desktops, and tablets running the Windows 10, Windows 8/8.1, Windows 7 operating systems. Works for all major computer manufactures (Dell, HP, Acer, Asus, Toshiba, Lenovo, Samsung).