With the recent Macro Hardening changes, you will notice that Excel 97-2003 and Word 2007 files are no longer supported, these can be converted by using Office Online as seen below:
Step 1
Login to Microsoft365 with you council account https://www.microsoft365.com/?auth=2
Step 2
Select "" and choose either Word or Excel
Step 3
If the file is saved on your OneDrive, use the Search function to find it. Otherwise select the "Upload" option near the search bar and navigate to where its saved.
Step 4
Once the file loads, select "Edit Workbook" (Excel) or "Edit Document" (Word) which will prompt to be Converted to the supported format
Step 5
Once the document is converted, you can now select "Editing" and "Open in Desktop".