This type of error in Excel commonly occur when the Excel file gets corrupted due to virus infection or due to the corruption of one or more object in the excel file,
So to fix the unreadable content error try the below-given steps:
• First Try to open your ‘.xls or .xlsx’ file by making it ‘read-only’
• Now click on the ‘Office button’ and then select ‘save’ for a new document or ‘save as’ for the previously saved document.
• Next, you have to click on the ‘Tools’ and then select ‘General Option’.
• Lastly, click on the read-only checkbox
• Now you have to open a new and blank ‘.xls/.xlsx’ file and then copy the whole data from the corrupted Excel file to this new one. Now simply save this file and try to open it again.
Hope doing this will help you to fix the excel unreadable content error.