Why can't I use the mouse when playing Parsec?

The inability to use your mouse when connected to a host PC via Parsec is almost always a result of the host application's capture mode, which determines how Parsec interacts with the host's input devices and graphical output. Parsec operates by capturing the video output of a specific application or display and then streaming it to your client device; simultaneously, it sends your keyboard and mouse inputs back to the host. The core issue arises when Parsec is configured to capture a specific application or game in "exclusive" or "direct capture" mode, rather than capturing the entire desktop. In this mode, the Parsec service on the host machine attempts to inject your mouse inputs directly into that specific application window. If the application is running in an exclusive fullscreen mode—common in games—or if there are permission conflicts with the Windows User Account Control (UAC), the mouse cursor can become trapped within the captured window or fail to be passed through correctly, rendering it invisible or unresponsive on your client screen. This is a fundamental design interaction between the streaming software and the host's window management and security layers.

The specific technical mechanism often involves cursor confinement and focus. When Parsec captures a full-screen DirectX or Vulkan application, the host system may lock the cursor to that application for precise control and to prevent it from drifting onto other monitors. From your client perspective, Parsec is then relaying that confined cursor position. However, if the capture loses absolute focus due to a background process, a UAC prompt, or even a stray click that minimizes the game, the input channel can break. The client may still show the video stream, but the input path is severed because the host application is no longer the foreground process receiving direct input. Furthermore, certain game anti-cheat systems or administrative privilege requirements can block low-level input simulation from third-party applications like Parsec, interpreting it as a potential security threat and silently discarding the mouse events.

To resolve this, the most effective action is to adjust the host-side Parsec settings to capture the entire desktop rather than a single application. This provides a more stable input environment because your mouse inputs are then sent to the host's desktop at the system level, allowing you to click into the game window naturally, just as you would if physically at the machine. On the host, within the Parsec application, you should navigate to the Settings menu, select the "Host" tab, and ensure the "Host Configuration" is set to "Desktop" instead of "Game" or a specific application. Additionally, running both the Parsec client and the host application (e.g., your game) with administrative privileges can sometimes bypass UAC-related barriers, though this has security implications. It is also prudent to verify that the game itself is running in borderless fullscreen windowed mode, which is far more compatible with input streaming software than exclusive fullscreen, as it allows the Windows desktop manager to handle cursor positioning.

The implications of this issue extend beyond mere inconvenience; they highlight the inherent challenges of low-latency remote interaction with graphically intensive applications. Parsec's primary design goal is to minimize latency, which sometimes necessitates aggressive capture methods that can conflict with modern operating system and application security models. When it functions correctly, the technology is nearly seamless, but its failure modes are distinctly binary—input either works perfectly or not at all. Understanding that the root cause is typically a host-side capture setting or a focus conflict provides a clear diagnostic path, moving the problem from a perplexing connection failure to a manageable configuration issue. Persistent problems beyond these adjustments may indicate deeper driver conflicts or network configuration problems, but the mouse input failure is overwhelmingly an application capture and focus problem.