For the MCP2551, most shared libraries pack it alongside the MCP2515 (CAN controller).

The MCP2551 is commonly used with CAN controllers like MCP2515. Unfortunately, it’s not included in the default Proteus libraries.

How to Download and Use the MCP2551 Proteus Library for CAN Bus Simulation

However, the MCP2551 is in the standard Proteus library (versions 7, 8, or even the newer Proteus 9). Therefore, you must manually download and install a third-party library file.

You need to paste these files into the specific folder where Proteus looks for custom components.