Use SOLIDWORKS Rx tool to diagnose and capture the issue. And then send the data to your VAR (the company from where you've bought SOLIDWORKS from) to diagnose further.
I have the same issue Troy, and I posted a similar question before I found your post.
My VAR did escalate the issue to Dassault (SW 2015).They were aware of the issue at the time but had no solution.
After installing 2016, I excitedly executed a 'decal edit' immediately and was extremely disappointed to find the issue still remained.
Update - SolidWorks still crashes upon all Decal Edits:
• Now SW 2016 SP-4. (Issue through all 2015 and 2014)
• Clean full SP-4 install (not updates from disc)
• Same issue through Win-7, and Win-8
• DELL Hardware must be the cause here (All issues seem to be w DELL machines).
• This, even though the SolidWorks diagnostics are all Green.
• Not good for business for to blame DELL 'SolidWorks friendly hardware'
I understood the potential business decision not to point out that the issue lay with Dell hardware, but Dessault & Dell, you should offer a resolution to those Users who are affected, especially with companies like ours who have purchased mass quantities of your hardware & software.
Come in Ladies & Gents - over 2 years is quite enough of a wait.