version.dat is considered a type of Dynamic Link Library (DLL) file. Dynamic Link Library files, like version.dat, are essentially a "guide book" that stores information and instructions for executable (EXE) files - like certutil.exe - to follow. These files were created so that multiple programs (eg. FortiClient) could share the same version.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 version.dat is attempted to be loaded either when FortiClient is starting up, or in some cases already running. Some of the most common version.dat errors include:
- Access Violation at address - version.dat.
- version.dat could not be found.
- Cannot find C:\Users\Tester\AppData\Local\Temp\ipsdb_expect-0\version.dat.
- Cannot register version.dat.
- Cannot start FortiClient. A required component is missing: version.dat. Please install FortiClient again.
- Failed to load version.dat.
- The application has failed to start because version.dat was not found.
- The file version.dat is missing or corrupt.
- This application failed to start because version.dat was not found. Re-installing the application may fix this problem.
Your version.dat file could be missing due to accidental deletion, uninstalled as a shared file of another program (shared with FortiClient), or deleted by a malware infection. Furthermore, version.dat file corruption could be caused from a power outage when loading FortiClient, system crash while loading version.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.