regAEBILO630 - Worked for me. Don't bother reading the rest of this form. Please refer to his answer here or above. 

"I'm posting this here to save someone the headache that I had to go through.

After installing Office 365 as a test, and then removing it - the excel options were going from QB.

I uninstalled, reinstalled, repaired, etc. etc. with no luck.

using regedit - Delete the 1.9 key under: (Right Click 1.9 Folder and click delete)

HKEY_CLASSES_ROOT\TypeLib\{00020813-0000-0000-C000-000000000046}

Then restart QB - problem solved." - AEBILO630

Unfortunately I have messed with this for a long time and finally it works. I had someone in the office install a newer version of Microsoft Excel for a book report they were doing then I downgraded back to 2010 and it stopped working. Then I bought a new computer that already had Office 365 and I uninstalled that and put my copy of 2010 back on and it was greyed out there too. I just fixed both computers with the above solution. Don't call Quickbooks, dont uninstall everything and reinstall, just do this above and you'll be fixed up.