I would remove him from the profiles he is not actually credited in.  I would not simply tic the uncredited box.

That being said, if you can provide evidence that the 'William Morgan Sheppard' credits are wrong, I have no problem ignoring those numbers, from the lookup tool, and using the next highest number.

Currently the credit lookup tool shows the following:

William Morgan Sheppard: 128 titles/200 profiles
W. Morgan Sheppard: 108 titles/231 profiles
Morgan Sheppard: 67 titles/118 profiles

Having checked the movie credits of only some of the DVDs in my collection, I can confirm that AT LEAST 21 titles and 25 profiles INCORRECTLY show a credit for William Morgan Sheppard in the online database. This means that the corrected results of the credit lookup tool show that William Morgan Sheppard is credited in NO MORE THAN 107 titles/175 profiles, i.e. less than W. Morgan Sheppard. (In addition, some of these incorrect 21 titles/25 profiles should be added to both W. Morgan Sheppard and Morgan Sheppard's credits, making each of their totals a little higher.)

It is also likely that W. Morgan Sheppard is the correct credit in "Wild at Heart", something which would further reduce William Morgan Sheppard's credits by 21 more profiles. I will check this later and update the thread. This thread can then be used as a reference when submitting Common Name changes.

Quoting EnryWiki:

Quote:
Quoting Behemot:

Quote:

Having checked the movie credits of only some of the DVDs in my collection, I can confirm that AT LEAST 21 titles and 25 profiles INCORRECTLY show a credit for William Morgan Sheppard in the online database.

Let me play devil's advocate for a moment. 
Do you actually own those 25 DVDs? Then you can correct them and the Credit Lookup will provide more correct results.
Or, you don't own all them. Then you can't be 100 percent sure of what's there, can you?, unless we assume that different editions and localities generally share the same credits (which I think we can safely assume, except for a few exceptions). 

I am not saying you are wrong, on the contrary I think you are right. 

No I don't own them, or else I would have corrected them. I realize that on rare occasions credits may vary on different releases, but like you say, this is much more uncommon than their being the same.

Anyway, I have personally verified that he is credited as follows in MY DVDs of the following movies - also added verified credits from other forum members (see below):

W. Morgan Sheppard
-American Gothic: The Complete Series
-Wild at Heart
-Needful Things
-The Prestige
-Transformers
-Babylon 5: The Complete First Season
-Star Trek VI: The Undiscovered Country
-Frasier: The Complete Second Season
-Quantum Leap: The Complete Fifth Season

Morgan Sheppard
-The Duellists
-The Elephant Man
-Hammer House of Horror
-The Sweeney: The Complete First Series
-Minder: Series 1 Part 3
-The Professionals: Dossier 2

And, as mentioned earlier, he is not credited under ANY name in Stephen King's "Kingdom Hospital".

And also personally verified:

W. Morgan Sheppard
-Babylon 5: The Complete First Season
-Star Trek VI: The Undiscovered Country

Quoting Unicus69:

Quote:
Green M&Ms to all three of you.

Where I come from, green M&Ms are for an entirely different purpose.     

Quoting Rutan:

Quote:
And also personally verified:
Morgan Sheppard

-Minder: Series 1 Part 3

Thanks! I've updated my earlier post to include this!