LR is multi-platform and will work on both Windows and Mac with the same serial number. You can buy from the following link if you have 64 bit Windows. After clicking "Buy" change from Full to Upgrade; then select your existing LR product from the drop-down menu and the correct pricing will be displayed. Then simply choose “Add to Cart” https://www.adobe.com/products/catalog/software._sl_id-contentfilter_sl_catalog_sl_softwar e_sl_mostpopular.html Or you can take a 30 day free trial via the Creative Cloud to test what’s new (some new features are only available to CC subscribers) and after the trial it’s possible to convert the CC version to the LR6 stand-alone version, upon purchase of a serial number and without any further installation. In either case make sure your computer meets the minimum system requirements. Compare Lightroom versions | Adobe Photoshop Lightroom CC Minimum system requirements https://helpx.adobe.com/lightroom/system-requirements.html
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