RMS 2.0 SP4 (2.0.0155) or higher is required for Windows 7.
Only Windows 7 Professional is supported (not Home Premium). 64-bit is not recommended for your POS lanes. You may have problems with OPOS drivers and integrated credit/gift card processing if deployed on a 64-bit POS lane PC.
Web based global gift card services like Mercury/Vantiv/Worldpay are not compatible with Windows 7 64-bit without a plug-in. Contact a help desk operator for details.
POS macros will not work with UAC enabled.
Windows 7 will display a compatibility error when installing RMS with SQL 2005 Express. You should bypass the error as SQL will be patched during a subsequent Windows Update. Or you should skip SQL Server installation if the PC will not be used as a database server.
Summary: The preferred hassle-free OS for POS lane stations is Windows 7 Pro 32-bit (x86). 64-bit is fine for any back-office PCs.
Window 10 compatibility:
Is Microsoft RMS compatibile with Windows 10? - Digital Retail Solutions (kayako.com)