Microsoft Excel is a powerful tool that allows users to input formulas, functions, calculations, and data into a Worksheet to obtain useful results. Additionally, users can insert various types of files into an Excel document using the Insert tab. However, there are times when Excel fails to work and blocks files from being inserted due to Trust Center issues. This may occur if the file is blocked by Trust Center, the workbook is locked, or if the file is corrupted.
To unblock a file via Trust Center settings, users must open Excel and navigate to File > Options > Trust Center. From there, click on Trust Center Settings and then File Block Settings. Untick the Open or Save boxes for the file type that needs to be opened or saved and click OK.
If the Worksheet or Workbook is locked, users can disable protection by selecting the Review Tab and going to the Protect category on the Ribbon. From there, select Unprotect Sheet or Unprotect Workbook and enter the required password.
Corrupted or damaged files may also cause Excel to reject file additions. In such cases, users must recover the corrupted files by following the instructions in a relevant article.
Administrative security policies may also prevent file additions in Excel on a work-related network. Users must determine which file types are not blocked and use those if possible. Alternatively, they can contact the system administrator to temporarily change the security settings to allow certain file types to be inserted in Excel.
Finally, if Excel displays an error message when attempting to insert a PDF file, it may be due to the Protected Mode feature from Adobe Reader. Users must open the PDF in Adobe Reader and disable Protected Mode before inserting the file again in Excel.