@陈墨
Which version of Excel are you using to open these excel files?
Did you open the Excel file via browser or Excel desktop client?
Please note, tag "office-excel-itpro" on Q&A forum focus more on general issues of Excel desktop clients.
If the workbooks opened via Excel desktop clients are changed to be messy code, please go to Control Panel > Clock and Region > Region > Administrative > Change System locale, you may choose a language which is same as the language used on Excel files.
Besides, it's recommended to repair workbooks, more detailed information, please refer to "Repair a corrupted workbook".
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