I've been banging my head against this issue for a week or so, trying various combinations of the below to no success:
- turning cloud saves on/off
- moving existing saves in case they are corrupt
- turning off Origin in game
- replacing/removing/repairing awc.dll and EACore.dll
What finally fixed it for me was a post from 2013 - http://answers.ea.com/t5/Mass-Effect-3/Mass-Effect-3-will-not-launch/td-p/1108260
-> In ...\Mass Effect 3\Binaries\Win32, I renamed atiags.dll, to make it appear that it was gone. Game fired right up, and has continued to do so.
For context, my specific errors I was getting were:
Problem signature
Problem Event Name: APPCRASH
Application Name: MassEffect3.exe
Application Version: 1.5.5427.124
Application Timestamp: 50d4cab0
Fault Module Name: ntdll.dll
Fault Module Version: 10.0.14393.479
Fault Module Timestamp: 58256ca0
Exception Code: c0000005
Exception Offset: 00047772
OS Version: 10.0.14393.2.0.0.256.48
Locale ID: 1033
Additional Information 1: 2beb
Additional Information 2: 2beba6fb4680d73a8c78ca7c24ccdb46
Additional Information 3: 1055
Additional Information 4: 10551cc64bcfba7d2297b81a9c0092f2
This is on a machine that played 130+ hours of Mass Effect 3 when it came out originally, but has had a couple of GPU upgrades since then, and runs Win10 instead of Win7 now. One of those GPU swaps was to change from team red to team green. Though I will note, this error persisted through Origin and Mass Effect 3 reinstalls, so I'm not sure why that ATI file is even present.
Hopefully this helps someone else who might be looking to mess with ME3 in anticipation for the Andromeda release. I figured if I was ever going to try "Citadel" now is the time.