registry.dll is considered a type of Dynamic Link Library (DLL) file. Dynamic Link Library files, like registry.dll, are essentially a "guide book" that stores information and instructions for executable (EXE) files - like MpSigStub.exe - to follow. These files were created so that multiple programs (eg. Extensions for Windows) could share the same registry.dll file, saving valuable memory allocation, therefore making your computer run more efficiently.
Unfortunately, what makes DLL files so convenient and efficient, also makes them extremely vulnerable to problems. If something happens to a shared DLL file, either it goes missing or gets corrupted in some way, it can generate a "runtime" error message. Runtime is pretty self-explanatory; it means that these errors are triggered when registry.dll is attempted to be loaded either when Extensions for Windows is starting up, or in some cases already running. Some of the most common registry.dll errors include:
- Access Violation at address - registry.dll.
- registry.dll could not be found.
- Cannot find C:\Program Files\Extensions for Windows\Extensions\Common\Registry\registry.dll.
- Cannot register registry.dll.
- Cannot start Extensions for Windows. A required component is missing: registry.dll. Please install Extensions for Windows again.
- Failed to load registry.dll.
- The application has failed to start because registry.dll was not found.
- The file registry.dll is missing or corrupt.
- This application failed to start because registry.dll was not found. Re-installing the application may fix this problem.
Your registry.dll file could be missing due to accidental deletion, uninstalled as a shared file of another program (shared with Extensions for Windows), or deleted by a malware infection. Furthermore, registry.dll file corruption could be caused from a power outage when loading Extensions for Windows, system crash while loading registry.dll, bad sectors on your storage media (usually your primary hard drive), or quite commonly, a malware infection. Thus, it's critical to make sure your anti-virus is kept up-to-date and scanning regularly.