Hello there,
This might be due to Icon cache corruption.
Open File Explorer > Folder Options > Views to show Hidden System Files.
Next, go to C:\Users%username%\AppData\Local folder.
Delete the hidden IconCache. db file. Reboot.
This action would purge and rebuild the icon cache.
Similar discussion here https://answers.microsoft.com/en-us/msoffice/forum/all/word-and-excel-icons-changed-into-blank-white/575202ea-534a-4804-9cea-a13e1457e5dd
Hope this resolves your Query !!
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