After upgrading from Windows 7 to Windows 10, you may find that some of your Office 2013 documents do not open and you receive one of the following errors:
See an example here :

Error While Opening Office Documents (Word/Excel/PowerPoint) After Upgrading to Windows 10

  1. Word: “Word experienced an error trying to open the file”
  2. Excel: “This file is corrupt and cannot be opened”
  3. PowerPoint: one of the following –
    • “The application was unable to start correctly”
    • “PowerPoint found a problem with <filename>”
    • “Sorry, PowerPoint can’t read <filename>”

Workaround 1: Run a command to correct folder permissions

  1. Highlight the following command, and press Ctrl+C to Copy it: icacls “%programfiles%\Microsoft Office 15” /grant *S-1-15-2-1:(OI)(CI)RX
  2. In Windows 10, press-and-hold or right-click on the Start button and choose Command Prompt (Admin).
  3. In the Command Prompt window, tap or click the upper left of the window to open the command menu. Choose Edit, and then select Paste to paste in the command.
  4. Press Enter to run the command. did not work for me.. So I went for the below one and got repaired.

Workaround 2: Run an online repair of Office

  1. In Windows 10, right-click on the Start button and choose Control Panel.
  2. Select Programs – Uninstall a program, or Programs and Features.
  3. Choose the entry for your Office program and select Change.
  4. Select Online Repair and click Repair.
Once the repair is complete, your files should open without any error.