The file extension LEX marks so-called Adobe Linguistic Library data. The Adobe Linguistic Library is a development package to provide language services such as spelling and grammar checking in Adobe products.
Among other things, LEX files contain dictionaries or words with the syntax description and are usually available for different languages. Lex files are usually installed in a folder that is accessible to all Adobe products.
LEX files can not be loaded directly, but appear in the presets of Adobe programs when installed correctly as an entry in the dictionaries or the language selection.
Most often resolving problems with opening LEX files is very simple. Just install an appropriate program that supports such files. All of the listed programs support LEX files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of LEX files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate LEX files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Adobe Linguistic Library applications is not on the list, select "Browse" option in order to manually locate the directory where Adobe Linguistic Library has been installed.
Sometimes problems with opening LEX files may not lie with the application itself, but can arise due to other causes, such as: