If you are unable to open an Excel 2010, Word 2010, or PowerPoint 2010 file from Outlook or from the Internet, and you get an error message, then you may want to try this solution.
In such cases Office 2010 may report the file as being corrupt. The exact Errors may include:
Excel: The file is corrupted and cannot be opened.
Word: Word Experienced an error trying to open the file.:
PowerPoint: PowerPoint found a problem with content in file. PowerPoint can attempt to repair the presentation.
In such a case you can try the following:
1) Open Control Panel
2) Open Administrative Tools
3) Open Component Services and expand the tree under Console Root to Computers > My Computer.
4) Right-click on My Computer and select Properties.
5) Select the Default Properties tab and set the following values:
– Default Authentication Level: Connect.
– Default Impersonation Level: Identify.
Microsoft KB2387587 explains that this happens if your DCOM security settings may have changed and they do not allow the temporary file structure that must be created. By carrying out the above suggestion you will set component security settings back to the defaults.