@magicalclick: NVM, turns out there's a variety of reasons why you might not be able to open a document on a WP:

  • You might not be able to edit a Microsoft Office document on your phone depending on what's in it or how it was last saved. Here are some of the more common things that make a document read-only on your phone.

    The file is:

    • Saved as an older type of Microsoft Office document, such as a Microsoft Word 97-2003 document (.doc), Microsoft Excel 97-2003 workbook (.xls), or Microsoft PowerPoint 97-2003 presentation (.ppt).
    • Digitally signed.
    • Marked as final.
    • Protected using rights management.
    • Protected with a password.
    • Protected with restricted editing rights.

    Microsoft Word documents are read-only if they have:

    • Track Changes enabled.
    • Frames.
    • Custom markup (custom XML, Structured Document Tags (SDT), or smart tags).
    • XML tags with unsupported values.

    Microsoft Excel workbooks are read-only if they have:

    • Functions that aren't supported on the phone. For info about which Excel functions are supported, see the Microsoft Support article about supported content in Excel Mobile.
    • Scenarios.
    • Data validation in one or more cells.
    • Array formulas.
    • Data tables.
    • Slicers.
    • Macros enabled.
    • Large column or row widths.
    • Formulas that contain links or references to other workbooks.
    • Formulas with structured references.
    • Formulas that contain references, content, or formatting beyond cell IV16384.
    • Formulas that are longer than 512 characters or have more than 30 arguments in them.
    • Tracked changes.
    • Dialog sheets.
    • XML markup that isn't formed correctly.
    • OLE objects or ActiveX controls.

    For Microsoft OneNote notebooks, you can't edit:

    • A page from a notebook that was sent as an email attachment.
    • A notebook that is shared on SkyDrive, a Microsoft SharePoint site, or a SharePoint Online site, and marked as read-only.
    • A notebook that has a corrupted page.

    For Microsoft PowerPoint presentations, you can only make certain types of edits on your phone. Some examples include editing text in a text box, adding or editing notes, changing the order of slides, or hiding slides. For more info about editing a PowerPoint presentation on your phone, see Use PowerPoint Mobile.