Game crashing to desktop (I've mentioned this before)

FWIW I haven't had that.

I've had crashes but they were the consistent crashes I've had since the game's inception. (Sometimes it'll crash as soon as I hit Multiplayer.)

***

I did have a bloody odd bug that was a new one to me. At least I think it's new to me.

I was on a laggy host, but managing. Objective wave comes up and it's Pizzas. So I run towards it, and I think I get it but something goes weird. The pizza turns invisible, but it doesn't look like I got it. Now, there was someone next to me so I figure they must've got it just before I did. Except... he doesn't have it either.

I start running around a bit, and then it dawns on me. I have the thing, it's just invisible. Now, like I just said, I was running around. But I didn't hear the "dropped pizza" sound. Now I get the inkling that maybe I have the damn thing on me but its invisible, and bugged so I can run with it.

With that in mind I ran to the drop-off zone, and waited in it for about 5-10 seconds, a fairly long while in game-time. But sure enough, the objective counter tics over to the next one and a new arrow pops up on my HUD properly.

Weird ass bug, and while I've played in modded lobbies that let you run with the pizza, this wasn't one of those. This was... a new one for me. (I think, now I just think I didn't realize I had the thing on me because I could run and it was invisible.)

Anyways, I like my bug a lot more than yours.

So, after a reinstall of Win10 I finally have ME3MP back up and running.

1: Thanks mainly to Mod Manager. And also Large Address Aware. And p0358 on Twitter.

2: No thanks to EA for the EA App. I wouldn't let whoever is in charge of that pile of steaming shit be in charge of making the tea.

rxsrt17
Okay, I understand better. Addressing your follow-up Q's:
3) re:Other stores. hmmm, no real insight here. I usually check Slickdeals.net for sales on anything (also some good, if opinionated, info on most any "deal" posted). You mentioned cdkeys, one of the gray market sellers. There are others but I just checked royalcdkeys and nothing there. So besides Steam, dunno, sorry.
4) Ah, understood (I have it on XBOX, so I know what you are talking about). Alas, on PC it is different . You are really paying for the account. So, sorry, if you want to play with your son, he needs his own game purchase and make an EA account (if he doesn't have one already) to claim it. Aside: it is not cross-platform either, so just PC account vs. PC account.
6) Hmm. I don't think purchase point matters vis a vis modding as all purchases eventually have you activate (and access?) through EA App. But I'm no expert here as I purchased all of mine straight from Origin/EA.
As to mods, that's more involved. I dabble in them. Some basics:
Get me3tweaksmodmanager
Many mods are available through that manager which accesses NexusMods (you'll want to register there)
It might be worth taking a peak here
I've made objectives mods, as have many others. When you get to that point, give a holler here or DM.

But for credits, it's easier. No Mod necessary:
enable console (use ME3tweaksMM, tools>Bink Bypass>Check ME3, tilde and tab are defaults, but you can change, also in "Tools")
Go into game. Enable with either console key.
Enter "grantmpcredits ####" (without the quotes. ### = any amount you want. You can do negative credits to remove them as well, which I've done after getting a ton from someone's modded lobby).

You can do a lot without mods, just with console commands.  See this thread.