WinFrame was a multi-user version of Windows NT 3.51 which was fully repackaged by Citrix Systems. At this stage of the product development Citrix Systems licensed the Windows NT 3.51 base operating system from Microsoft. The core development that Citrix delivered was the MultiWin engine. This allowed multiple users to logon and execute applications on a WinFrame server. Citrix was to later license the MultiWin technology to Microsoft, forming the basis of Microsoft's Terminal Services.
Repackaged versions of Windows 95, with Citrix WinFrame Client included, were also available from Citrix.
WinFrame has since been superseded by Citrix MetaFrame and more recently Citrix XenApp.