So this morning, I learned something new. New, and horrible. Let me explain:

We have an ERP application that runs from a shared network drive, since most of its backend is stuck in the 90s. All it stores on user's PCs is a temp directory for its built-in print spooler. Because I guess the Windows print spooler wasn't buggy enough for their liking.

I visited our warehouse one town over from the office this morning. Understandably, they feel a little bit like the red-headed step child that gets forgotten, so leadership decided that an IT guy had to drop by once a week. All this did was make them stop creating tickets altogether, and instead wait up to 5 days for us to fix the problem in person. Anyway, this week it was my turn.

I get there, and one guy mentions to me that he's having a strange issue: $WarehouseGuy: "Hey, so I know this sounds insane, but when I set this small label printer that's at my desk as default printer on my PC, it applies to my colleagues PC, too. And the other way around." $Me: "wat" $WG: "This started like two months ago. I think with an update of the ERP application. We've agreed that the other guy will set his label printer as default, and I need to switch it every time." $Me: "WAT" $WG: "Yeah, let me show you."

So he opens our ERP application, opens the label module and goes to print, which triggers a built-in Windows print dialog. He chooses the USB label printer connected to his PC and clicks "OK". Now he's back in the ERP application, which now presents him with a checkbox for "Permanently store these settings". He checks it and prints.

At this point, I'm thinking it's an issue with our ERP app. I check that his temp directory is not set to a network drive by mistake, that he's logged in using his own user account and such. Now I'm thinking, it might be that the application update introduced a bug where it mistakenly stores its settings globally in the shared drive instead of in the local temp folder, as intended.

We wander over to his colleague, who is using a completely different, third-party label printing application. He opens the print dialog, which by default now selects the USB label printer instead of whatever he was using before.

Let me repeat. Him checking "Permanently store these settings" inside of the ERP application made a computer six feet away change the printer settings of a completely different application.

I almost dropped my coffee. It's not like I thought he was lying to me, but this is just not possible. This is not something that computer would ever do. Usually, when presented with a problem, I have a rough guess and can immediately start troubleshooting. But I'm dumbfounded.

Could the ERP application somehow synchronize these settings? "No," I'm thinking, "it's not agile enough for that. He didn't even have that app focused." I start googling for "Windows changing default printer makes other computer change default printer" but feel absolutely ridiculous in doing so.

Meanwhile, $WG goes: "Yeah, so when $BossOfIT was there the other week, he mentioned something about an issue with Microsoft, but he didn't have time to take a look." This is pretty vague, but it gave me an suspicion. A horrible, horrible suspicion.

I open the Windows printer settings on $WG's colleague's pc. I scroll past all the different network printers to the global settings. And I see it. Another one of those Microsoft's additions that is absolutely useless, fixes nothing, causes confusion, doesn't ever really work, and - is enabled by default.

"Let Windows manage my default printer - ON"

"No," I'm thinking... "it can't... they wouldn't. They wouldn't, right?"

OH BOY THEY WOULD!! I checked $WG's pc, and he didn't have that setting enabled. Checking the box in the application set his Windows default printer as the USB label printer. Which caused his collegues PC to wirelessly transfer this setting to itself. Once disabled, the madness stopped. The world made sense again. I think the other IT guys back in the office might've heard me scream. It's not even 8:30 yet. I need another coffee.