It seems like you have come across a file with no file extension. The file extension tells Windows what type of file it is. Normally a file has a file extension, e.g. .PDF, that can be associated with a viewer for .PDF files, but when the file extension is missing, Windows does not know what to do with the file, as it doesn't know what type of file it is.
If the file was created on a Unix or Linux system, it is probably a plain text file you can open with most file viewers. If not, you may have saved the file using an incomplete file name when downloading it from the Internet. Free File Viewer is able to open more than 200 different types of files. The program is free, and after you have installed it, you simply right-click on your file and select "Open with Free File Viewer". We have verified that it works with extension-less files. It could also be that the file associations are broken on your Windows installation. We recommend that you run a free scan with Registry Cleaner Pro to see if your system is damaged.
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File.org aims to be the go-to resource for file type- and related software information. We spend countless hours researching various file formats and software that can open, convert, create or otherwise work with those files.
If you have additional information about the Extension-less file format or software that uses files with the Extension-less suffix, please do get in touch - we would love hearing from you.