Here’s a clear, proper explanation about on Windows 11 — what it is, why you need it, and the correct way to obtain it without risking malware. What is MSVCR100.dll? MSVCR100.dll is a Microsoft Visual C++ Redistributable file. It belongs to Visual C++ 2010 (version number 10.0). Many older games, engineering tools, and third-party software require this file to run.