Open Command Prompt as Administrator and run:
cd "C:\Program Files\MATLAB\MATLAB Runtime\v99\runtime\win64"
regsvr32 mclmcrrt9-9.dll
Note: Many MCR DLLs are not COM-registerable, so this may fail. If it fails, a reinstall is the best option.
Q1: Can I download mclmcrrt9-9.dll from a DLL website? A: Strongly discouraged. Those sites often provide outdated, corrupt, or infected files. Always use the official MCR installer. mclmcrrt9-9.dll
Q2: Do I need MATLAB to use this DLL? A: No. The MCR is free and does not require a MATLAB license.
Q3: Why does my program need version 9.9 specifically? A: Because the developer compiled it against that version’s API. MATLAB/MCR is not backward-compatible across major versions. Open Command Prompt as Administrator and run: cd
Q4: What is the difference between MCR 9.9 and 9.9.0? A: The third number is a patch release. Usually, MCR 9.9.x can run applications built for 9.9.0, but exact matching is safest.
Q5: Can I install multiple MCR versions side-by-side? A: Yes. You can have MCR 9.8, 9.9, and 9.10 installed simultaneously. Each resides in its own folder. Note: Many MCR DLLs are not COM-registerable, so
Some developers bundle the required MCR DLLs directly inside their application folder. This avoids PATH issues. If this is the case, do not try to install a separate system-wide MCR; it may cause version conflicts.
There are three primary reasons for these errors:
Yes. You can have MCR 9.9 (v99) and MCR 9.12 (v912) side by side. Each has its own folder. However, they cannot be used interchangeably.