Before you can export Excel spreadsheet from .xlk backup to a PDF document, you will have to first recover it using Microsoft Excel. As these files were used in Excel 2000, it may be possible that you will need that particular version of Excel to recover the backup files.
Convert Microsoft Excel backup file to Adobe Portable document format.
We found 2 software records in the database related to .xlk to .pdf file format conversion.
Microsoft Windows software - convert xlk to pdf on Windows
A popular spreadsheet application distributed with Microsoft Office suite
Convert from xlk file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned xlk to pdf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert xlk to pdf on OS X
A popular spreadsheet application from the Microsoft Office suite