What Is an XLK File?

This article describes what an XLK file is and how to open or convert one.

What Is an XLK File?

A file with the XLK file extension is a backup file created by Microsoft Excel. It's built automatically while an XLSX or XLS file is being edited.

Excel does this in case something goes wrong with the document. If, for example, the file is corrupted to the point that it can't be used any longer, the XLK file acts as a recovery file.

XLK files may also be created when exporting information from Microsoft Access into Excel.

The BAK file format is another backup file used in Excel.

How to Open an XLK File

XLK files are most commonly opened using Excel, but the free LibreOffice Calc program can open them, too.

Your XLK file is most likely an Excel backup file, but something else you can try to see if it's in another format is to open it with a text editor. Even if the file isn't readable/usable, you'll be able to see if there's any text within it that might help you determine what program was used to build it, which might lead you to a compatible file opener.

How to Convert an XLK File

Opening an XLK file in Excel works just like when opening a normal workbook. This means you can use Excel's File > Save As menu to convert one to any of Excel's other formats.

LibreOffice Calc supports some of the same formats as Excel. You can convert an XLK file in Calc by opening the file and then using the File > Save As option. It can also be converted to PDF with Calc's File > Export menu.

Still Can't Open the File?

If the file isn't behaving well with Excel, double-check the file extension. You might have a different file that's stored in a completely unrelated file format. This can happen if you've misread the file extension.

For example, an XLX file has nothing at all to do with Excel. If you try opening one in Excel, you'll get an error.

On the other hand, a number of other file types are used in Excel, and they, too, look very similar: XLB, XLL, and XLM are a few. They work with Microsoft's program just fine, so confusing one of those for an XLK file isn't actually an issue.

More Information on XLK Files

You can enable Excel backups on a per-document basis. When you go to save your file, but before you actually save it, go to Tools > General Options. Then check the box next to Always create backup to force Excel to keep a backup of that specific document.

XLK files are really a version behind the current one that you've saved. If you save the file once and enable the backup, the XLSX/XLS and XLK file will be saved together. But if you save it again, just the original will reflect those changes. Save it once more and the XLK file will have the changes from the first and second save, but only the XLSX/XLS file will have the most recently saved edits.

The way this works means that if you make a bunch of changes to your spreadsheet, save it, and then want to revert to the previous save, you can just open the XLK file.

Don't let that all confuse you. For the most part, XLK files pop in and out of existence automatically and help to make sure you don't lose your data if something unfortunate happens to the open file.