Message: Macros may contain viruses

Microsoft Excel
C:MySpreadsheet.xls contains macros.
Macros may contain viruses. It is always safe to disable macros, but if the macros are legitimate, you might lose some functionality.
Disable Macros Enable Macros More Info
I work as a data entry. My job requires transferring information to MS Excel. Several times, I have encountered this kind of error. What does this mean?
How do I respond to this prompt? What will I do if the macros contain viruses?
