Gantt Export to Excel

When trying to export to Excel we get the following “errors” and then the dates does not show in the Gantt:

  1. Excel found unreadable content in "KinematikPPMProgramandProjectManagement.xlsx’. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes.

  2. Excel completed file level validation and repair. Some parts of this workbook may have been repaired or discarded.

Please advise as this is critical on our side. Thank you.

Please send an example of the wrongly generated excel file ( you can attach it here, or send directly to with a reference to this post )