1. Context: Unity and RI.Hid

   RI.Hid refers to Unity's Raw Input for Human Interface Devices (HID), which is used to handle input devices like controllers, keyboards, and mice.
   The error indicates a failure in creating a communication pipe for handling device input.

2. Key Error Detail

   e7 Alle Pipeinstanzen sind ausgelastet.
   This is a Windows system error translated as:
   "All pipe instances are busy."

It means that the system has reached the maximum number of available named pipe instances for inter-process communication. Named pipes are often used for transferring data between applications or between threads within the same application.

3. Possible Causes

   Device Driver Conflict:
   A connected input device (e.g., game controller, VR headset, or HID) has a faulty driver or is incorrectly configured.
   Pipe Resource Exhaustion:
   Unity or another process on the system has opened too many input device connections, hitting the system's limit.
   Multiple Input Devices:
   Too many input devices connected simultaneously, causing Unity to attempt to register each one, exhausting pipe resources.
   Background Applications:
   Other processes may also be using named pipes, leaving no resources available for Unity.
   Unity or Plugin Bug:
   A bug in Unity’s input system or a plugin might be causing a resource leak, keeping pipes open unnecessarily.

4. Steps to Resolve

   Check Connected Devices:
   Disconnect unnecessary peripherals like controllers, VR headsets, or other USB devices.
   Restart Unity and the computer.

   Update Drivers:
   Update or reinstall drivers for input devices and check for firmware updates.

   Check Named Pipe Limits:
   Increase the limit for named pipes in Windows if this is a recurring issue:
   Open Regedit.
   Navigate to:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters
   Check or add the MaxInstances key (DWORD) and set it to 50 or higher.

   Unity Settings Check:
   Go to Edit > Project Settings > Input System Package and verify the configuration.
   Disable unused input backends if not required.

   Plugins or SDK Conflicts:
   Check if any input-related plugins or SDKs (e.g., VR/AR libraries) are causing conflicts. Disable plugins temporarily to isolate the issue.

   Rebuild Unity Library Cache:
   Delete the Library folder in your Unity project and reopen Unity to force a rebuild.

   Enable Logs for Debugging:
   Enable verbose logging for Unity input devices to track the exact source of the issue.

5. Further Investigation

If the problem persists, you may need to:

• Check Windows Event Logs for additional errors related to pipes or device connections.
• Update Unity to the latest version if using an older build.
• Test the project on another machine to determine if it's a hardware-specific issue.