engidx.dat is considered a type of Dynamic Link Library (DLL) file. Dynamic Link Library files, like engidx.dat, are essentially a "guide book" that stores information and instructions for executable (EXE) files - like AppInstaller.exe - to follow. These files were created so that multiple programs (eg. Microsoft Visio Premium 2010) could share the same engidx.dat 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 DAT 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 engidx.dat is attempted to be loaded either when Microsoft Visio Premium 2010 is starting up, or in some cases already running. Some of the most common engidx.dat errors include:
- Access Violation at address - engidx.dat.
- engidx.dat could not be found.
- Cannot find C:\Program Files (x86)\Microsoft Office\Office14\engidx.dat.
- Cannot register engidx.dat.
- Cannot start Microsoft Visio Premium 2010. A required component is missing: engidx.dat. Please install Microsoft Visio Premium 2010 again.
- Failed to load engidx.dat.
- The application has failed to start because engidx.dat was not found.
- The file engidx.dat is missing or corrupt.
- This application failed to start because engidx.dat was not found. Re-installing the application may fix this problem.
Your engidx.dat file could be missing due to accidental deletion, uninstalled as a shared file of another program (shared with Microsoft Visio Premium 2010), or deleted by a malware infection. Furthermore, engidx.dat file corruption could be caused from a power outage when loading Microsoft Visio Premium 2010, system crash while loading engidx.dat, 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.