Why Can’t I Use My Codec Plug‑in in Steinberg Hosts? (Cubase / WaveLab)

Modified on Wed, 30 Jul at 4:47 PM

Summary / Introduction

There is a known compatibility issue affecting Pro‑Codec and Codec Toolbox plug‑ins when used in certain Steinberg hosts such as Cubase and WaveLab.
In these cases, the host is unable to locate a required library file, which prevents the plug‑in from loading correctly.

This guide explains the cause and provides a temporary workaround until a permanent fix is released.

Affected Products

Pro‑Codec
Codec Toolbox

Affected Hosts

Steinberg Cubase
Steinberg WaveLab

Cause

The issue is due to the host being unable to locate the mmtisobmff.dll dynamic library in its default system folder.
Without this file in a location the host can read, the plug‑in fails to load.

Workaround

Important: This is a temporary solution. We plan to address compatibility in a future update.

Close all Steinberg applications before making changes.
On your system, open the folder:
```
C:\Windows\System32\
```
Locate the file:
```
mmtisobmff.dll
```
Copy (or move) this file to the Sonnox VST3 plug‑in directory:
```
C:\Program Files\Common Files\VST3\Sonnox
```
Relaunch your Steinberg host and check that your Sonnox Codec plug‑in now loads correctly.

Notes & Safety

Copy vs Move: We recommend copying rather than moving the file, so it remains in its original location for other applications that may rely on it.
Permissions: You may need Administrator rights to copy files into Program Files directories.
System File Warning: Do not rename or delete mmtisobmff.dll. This is a valid Windows system component.