libmsisac.dll is considered a type of Dynamic Link Library (DLL) file. Dynamic Link Library files, like libmsisac.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. Nimbuzz Messenger) could share the same libmsisac.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 libmsisac.dll is attempted to be loaded either when Nimbuzz Messenger is starting up, or in some cases already running. Some of the most common libmsisac.dll errors include:
- Access Violation at address - libmsisac.dll.
- libmsisac.dll could not be found.
- Cannot find C:\Program Files (x86)\Nimbuzz\lib\mediastreamer\plugins\libmsisac.dll.
- Cannot register libmsisac.dll.
- Cannot start Nimbuzz Messenger. A required component is missing: libmsisac.dll. Please install Nimbuzz Messenger again.
- Failed to load libmsisac.dll.
- The application has failed to start because libmsisac.dll was not found.
- The file libmsisac.dll is missing or corrupt.
- This application failed to start because libmsisac.dll was not found. Re-installing the application may fix this problem.
Your libmsisac.dll file could be missing due to accidental deletion, uninstalled as a shared file of another program (shared with Nimbuzz Messenger), or deleted by a malware infection. Furthermore, libmsisac.dll file corruption could be caused from a power outage when loading Nimbuzz Messenger, system crash while loading libmsisac.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.