Various features were added or improved over Windows Server 2008 R2 (with many placing an emphasis on cloud computing), such as an updated version of Hyper-V, an IP address management role, a new version of Windows Task Manager, and ReFS, a new file system.

It is the final version of Windows Server that supports processors without CMPXCHG16b, PrefetchW, LAHF and SAHF.

[7][8] Microsoft introduced Windows Server 2012 and its developer preview in the BUILD 2011 conference on September 9, 2011.

[11] On February 16, 2012, Microsoft released an update for developer preview build that extended its expiry date from April 8, 2012 to January 15, 2013.

[14] As of September 23, 2012, all students subscribed to DreamSpark program can download Windows Server 2012 Standard or Datacenter free of charge.

[16] Coupled with fundamental changes in the structure of the client backups and the shared folders, there is no clear method for migrating from the previous version to Windows Server 2012.

There is also a third installation option that allows some GUI elements such as MMC and Server Manager to run, but without the normal desktop, shell or default programs like File Explorer.

[17] The operating system, like Windows 8, uses the Metro-based user interface unless installed in Server Core mode.

Unlike the Windows 8 version of Task Manager (which looks similar), the "Disk" activity graph is not enabled by default.

The CPU tab no longer displays individual graphs for every logical processor on the system by default, although that remains an option.

The IPAM is used for the management and monitoring of Domain Name System (DNS) and Dynamic Host Configuration Protocol (DHCP) servers.

[32] Many new features have been added to Hyper-V, including network virtualization, multi-tenancy, storage resource pools, cross-premises connectivity, and cloud backup.

Major new features of ReFS include:[39][40] Some NTFS features are not supported in ReFS, including object IDs, short names, file compression, file level encryption (EFS), user data transactions, hard links, extended attributes, and disk quotas.

[59][60][61] Simon Bisson of ZDNet described it as "ready for the datacenter, today,"[59] while Tim Anderson of The Register said that "The move towards greater modularity, stronger automation and improved virtualisation makes perfect sense in a world of public and private clouds" but remarked that "That said, the capability of Windows to deliver obscure and time-consuming errors is unchanged" and concluded that "Nevertheless, this is a strong upgrade overall.

"[60] InfoWorld noted that Server 2012's use of Windows 8's panned "Metro" user interface was countered by Microsoft's increasing emphasis on the Server Core mode, which had been "fleshed out with new depth and ease-of-use features" and increased use of the "practically mandatory" PowerShell.

[63] Paul Ferrill wrote that "Windows Server 2012 Essentials provides all the pieces necessary to provide centralized file storage, client backups, and remote access,"[64] but Tim Anderson contended that "Many businesses that are using SBS2011 and earlier will want to stick with what they have", citing the absence of Exchange, the lack of ability to synchronize with Active Directory Federation Services and the 25-user limit,[65] while Paul Thurott wrote "you should choose Foundation only if you have at least some in-company IT staff and/or are comfortable outsourcing management to a Microsoft partner or solution provider" and "Essentials is, in my mind, ideal for any modern startup of just a few people.

In order to provide customers the standard transition lifecycle timeline, Microsoft extended Windows Server 2012 and 2012 R2 support in March 2017 by 9 months.

This will mark the final end of all security updates for the Windows NT 6.2 product line after 14 years, 2 months and 12 days and will also mark the final end of all security updates for the Windows NT 6.3 product line after 13 years, 1 month and 16 days.