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Windows DLL Errors

The Windows operating system uses files called Dynamic Link Libraries, or DLL files, to help programs and the OS share commonly used functions. A Dynamic Link Library is a collection of small programs that an executable can access in order to perform a certain function.

When a program needs a particular function, it calls the appropriate DLL and then loads the DLL’s code. For example, a program can use a DLL for functions such as printing rather than having its own unique code for this process. This makes the programmer’s job easy because he doesn’t have to write code for a common process that already exists. It also makes the computer perform better because as a result, many programs share the DLL and take up less resources such as hard drive space or RAM.

DLLs only load on an “as needed” basis. This helps programs to perform as many functions as possible yet only access the functions when needed, keeping memory usage to a minimum. For example, programs that use a DLL to control printing won’t load the required printing DLL until the user actually tells the software to print something. Many times a user will open a program such as a word processor, do their work and then close the program without printing anything. Because the printing DLL was never needed, it was never loaded.

Additionally, many programs can use and access the same DLL simultaneously. With printing as our example, you can send documents to the printer from your word processor and your spreadsheet at the same time without any conflicts or adverse effects.

While Windows DLL files have made computing more streamlined, Windows DLL errors do occur on a regular basis. A program may fail to open, crash, or a pop up screen may display errors such as:

• A required DLL was not found
• Out of date DLL
• DLL is missing or corrupt
• Caused an invalid page fault in DLL

Windows DLL errors occur for many reasons. Oftentimes a failed software installation will corrupt or replace DLL files. A successful installation can do this too. Many times a new software program will replace a Windows DLL with a different version which is fine for the new software program but not so great for the older programs that use the other version.

Uninstalling software also can cause DLL’s to go missing. The program being uninstalled may remove the associated DLLs without regard to other programs that may also need them. Usually uninstall programs give users a choice to keep the questionable DLLs but users may inadvertently click “OK” or believe it’s best to remove the DLL as the software suggests.