Growth in US Mac shipments hit more than 25% in the final quarter of last year, outperforming that of all PC makers. Only Acer came close with 20% growth, while market leaders HP and Dell both saw their shipments decline year-on-year.A market intelligence company has suggested a key factor may be Microsoft forcing businesses to replace millions of existing PCs Strong growth in Mac shipmentsCanalys reports that US Mac shipments in Q4 of last year grew 25.9% year-on-year, exceeding that of any PC maker. This boosted Apples share of the (non-tablet) computer marker gew from 14.4% to 17.1%.Acer and Lenovo also saw growth, though at lower levels. Acer saw 20% growth, while Lenovo saw shipments increase by 11.8%.Notably, both market leaders HP and Dell saw their combined market share drop below 50%. HP shipments fell 3.6%, and Dell 2.4%.Microsofts Windows 10 move likely a factorMicrosoft last year announced that it would be dropping support for Windows 10, the move taking effect in October of this year. This includes ending both technical support and security fixes, making it unsafe to continue using the OS.After 14 October 2025, Microsoft will no longer provide free software updates from Windows Update, technical assistance, or security fixes for Windows 10. Your PC will still work, but we recommend moving to Windows 11. Windows 11 offers a modern and efficient experience designed to meet current demands for heightened security.There are millions of older PCs out there unable to run Windows 11, meaning businesses are being forced to replace them.Since they have to replace the machines anyway, Canalys suggests that some may have taken the decision to use it as an opportunity to switch from PCs to Macs.The Windows refresh cycle provides fertile ground for Apple to target both consumers and businesses that may be open to switching operating systems. Historically, manageability and compatibility issues were highlighted as reasons for larger commercial customers to eschew Apple products. However, many of those issues have been addressed by Apple, and along with more competitive pricing and a revamp of its channel partner program later this year, 2025 is set to see Mac make market share gains within the commercial segment.Our Apple @ Work column has regularly highlighted the continued growth of Mac adoption in the enterprise sector.Highlighted accessoriesPhoto byLinus MimietzonUnsplashAdd 9to5Mac to your Google News feed. FTC: We use income earning auto affiliate links. More.Youre reading 9to5Mac experts who break news about Apple and its surrounding ecosystem, day after day. Be sure to check out our homepage for all the latest news, and follow 9to5Mac on Twitter, Facebook, and LinkedIn to stay in the loop. Dont know where to start? Check out our exclusive stories, reviews, how-tos, and subscribe to our YouTube channel