C2R

C2R, in computing, most commonly refers to Click-to-Run, Microsoft’s streaming deployment technology for Office products. Click-to-Run packages Office as a streaming, per-user application with built-in updates, rather than a traditional per-machine MSI installation.

Overview and operation: C2R streams a portion of the Office suite during installation, while remaining components are downloaded as needed. This enables smaller initial downloads and faster setup, which is particularly relevant for Microsoft 365 deployments. Office installed via C2R runs in a virtualized or containerized environment that isolates the suite from the operating system to improve compatibility and simplify updates.

Implementation and maintenance: C2R updates are delivered through Microsoft’s update infrastructure and can be installed via Windows Update or Microsoft Update. The Office components are cached per user and installed to the program files location appropriate for the Office version in use (for example, Office 2013, 2016, 2019, or Microsoft 365). In many environments, installations are per-user, though enterprise scenarios may use centralized management.

Advantages and limitations: The approach reduces initial network bandwidth, enables rapid deployment, and simplifies maintenance by delivering updates automatically. It can, however, rely on an internet connection for streaming and updates, which may be a consideration for offline or restricted environments. Some organizations still use MSI-based deployment for certain needs or legacy compatibility.

Notes: The term C2R is most often associated with Microsoft Office, but abbreviations can have other meanings in different technical contexts.