win_thumbnail.dll is considered a type of Dynamic Link Library (DLL) file. Dynamic Link Library files, like win_thumbnail.dll, are essentially a "guide book" that stores information and instructions for executable (EXE) files - like allplan_start.exe - to follow. These files were created so that multiple programs (eg. Cinema 4D) could share the same win_thumbnail.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 win_thumbnail.dll is attempted to be loaded either when Cinema 4D is starting up, or in some cases already running. Some of the most common win_thumbnail.dll errors include:
- Access Violation at address - win_thumbnail.dll.
- win_thumbnail.dll could not be found.
- Cannot find C:\Program Files\Maxon Cinema 4D R21\resource\libs\win64\win_thumbnail.dll.
- Cannot register win_thumbnail.dll.
- Cannot start Cinema 4D. A required component is missing: win_thumbnail.dll. Please install Cinema 4D again.
- Failed to load win_thumbnail.dll.
- The application has failed to start because win_thumbnail.dll was not found.
- The file win_thumbnail.dll is missing or corrupt.
- This application failed to start because win_thumbnail.dll was not found. Re-installing the application may fix this problem.
Your win_thumbnail.dll file could be missing due to accidental deletion, uninstalled as a shared file of another program (shared with Cinema 4D), or deleted by a malware infection. Furthermore, win_thumbnail.dll file corruption could be caused from a power outage when loading Cinema 4D, system crash while loading win_thumbnail.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.