Explanation of DLL files and Troubleshooting

DLL stands for Dynamic Link Library.

 

DLL Files are similar to EXE files. They hold a portion of programming code that can be swapped in an out of memory.

 

The programming code within a DLL file could be written into the EXE file. The problem is if the programming code is written into the EXE, it will have to be held in memory the entire time the application is running, taking up unnecessary resources.

 

The executable file that runs the DLL file must know where the DLL is. There are a couple of places the executable will look for the DLL file.

• The folder that the executable resides.
  • This is simply the path to the executable file.
• Sometimes the path of the DLL will be hard coded in the executable.
  • In this scenario, the DLL file would usually be in a sub directory of the application and the DLL file would have to be there in order for the application to run properly.
• The windows registry
  • The windows registry will store information on the system DLL’s. The reason for this is because a lot of DLL files will be shared between applications. There is a windows application names Regsrv.exe or Regsrv32.exe, typically resides in the C:\Windows\System32\ directory, which will add this entry into the registry for the DLL file. The command to register a DLL would typically be “Regsrv32 C:\PathToDllFile\DllFileName.dll”

 

Common causes of DLL file errors:

• Missing DLL file
• DLL file is not registered
• DLL file is not in the path it was registered to
• The DLL file is not the correct version for the application that is trying to use it
• The DLL file is corrupted
• There were programming errors in the DLL file or programming errors in the executable that was calling the DLL file  

 

Examples:

Access violation at address ???????? in module DllFileName.dll

This application has failed to start because DllFileName.dll was not found. Reinstalling the application may fix this problem.

DllFileName.dll missing or corrupt: Please re-install a copy of the above file.

ExecutableFileName.exe caused an invalid page fault in module DllFileName.dll.

Illegal Exception ModuleName in module DllFileName.dll at ????????. Floating Point Division By Zero.

Integer Divide by Zero in module DllFileName.dll at ????????.

 

Possible Solutions:

• You can start with a reboot; this will refresh the registry and ensure none of the applications have the wrong path stored in memory.
• Ensure the DLL file is in the proper location.
• Register the DLL.
• Reinstall the application utilizing the DLL.
• Replace the DLL file with a known good one.
• Copy the DLL file into the same location as the executable.