The unicows.dll file is the main dll file from what is known as the Microsoft Layer for Unicode (MSLU). The unicows.dll file is actually intended to be used on Win9x and WinMe operating systems, and its purpose is to provide a layer over the Win32 API, allowing developers to create a single Unicode version of their program.

On Windows XP, it appears that this file is not needed because XP provides such support for Unicode by itself. However, a rather high number of computer users are having problems with the unicows.dll file, usually getting error messages when attempting to run certain progams, mainly because they try to use programs that need to call this file, even if they are placed on a Windows XP operating system. If the the unicows.dll file is missing or corrupted, applications depending on it will fail to run.

The solution is to download and place on your system the Platform Software Development Kit Redistributable - Microsoft Layer for Unicode directly from Microsoft. The unicows.dll file is included in a self install executable that you can download from the specified location. When running the unicows.exe package, you will be prompted to specify a folder on your hard disk. Use any folder you want to extract the files. Then copy the unicows.dll inside your main application folder, where the program you want to run is installed. If the application still fails to run, you may need to copy the unicows.dll to what is called the Windows System folder (more info about this folder is shown below).

Important note: the Windows System folder can be different depending on operating system and the install path that was originally used when your Windows Operating system has been installed. The defaults for this folder are:
- C:\Windows\System32\ on Windows XP
- C:\WINNT\System32\ on Windows NT and Windows 2000
- C:\Windows\System\ on Windows 9x and Windows ME