I actually recall fighting this one before:
Exception code: 0xc0000005
It was a long time ago, but it was either caused by bad registry entries or bad RAM. Not even FileMaker related, but some IT task I was doing.
I am assuming that you have both FMPA 14 and 15 installed on the same machine? That may be a redundant cause of the issue.
Do you have an alternate PC that you can install FMPA 15 on cleanly and test it there?
Many thanks for your advice. I do have 14 and 15 installed on the same machine. 15 always launches first of course when opening the downloaded dbs!
I can get access to one where I can do a 15 install only, tho it may take a few days. Will try it and see what happens.
Please forgive any subsequent delay in reply therefore and bearing with me.