From the POD: MODIFYING_AND_REWRITING_EXCEL_FILES
An Excel file is a binary file within a binary file. It contains several interlinked checksums and changing even one byte can cause it to become corrupted. As such you cannot simply append or update an Excel file. The only way to achieve this is to read the entire file into memory, make the required changes or additions and then write the file out again.

In reply to Re: a stubborn excel file by toolic
in thread a stubborn excel file by biohisham

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