Check the document tab for this specific product - Document Language = US English, Document Status = Available, Classification = MSDS.

Verify the product has been assigned to an Inventory Location

If 1. and 2. check out fine, then retrieve the original MSDS document associated with the Product Record, and save it to the hard drive (e.g., onto your desktop).

Re-import the document to see whether there may have been a "glitch' in  the initial file import process.

Repeat Steps 1 and 2.  Save your changes.

Access the web interface to see whether the MSDS appears.

OR

If they are using a v5.0.0 then there is a bug where the wizard is not inputting the synonyms, thus making them unsearchable on the web interface. You will need a v5.0.1d or higher update.