I'd like to revive this thread/issue. 
 
Seems to be a common issue. I even downgraded the firmware as suggested in the previous posts. Is there *any* update on this from EVGA staff? 
 
Seems like neither EVGA peripherals i have want to work correctly upon turning on my PC. The mouse disconnects when I lift for the first 30 seconds of usage, then says "USB device unrecognizable" on windows banner, until i replug the device back in. Then it's a diceroll if it happens again. I noticed i can reproduce the issue by lifting the mouse up and turning it upside down. If there is a physical component to this, that's just a shame,. but to me if it was an actual physical problem it would happen more than just a few times when booting and then be good the rest of the day. 
 
My Z15 keyboard 50/50 turns on with the PC. That's less annoying but still shouldn't be expected to have to unplug and plug your peripherals daily.  
 

btarb24
Has it been confirmed that this is a solder issue and that reflowing resolves it permanently?  

I've got two x15 mice and both have this problem.

Where did you see this? Do you have more details?

I am now on my 4th X15 mouse and they're all having the same issues.  Not only do they all have the same issue, they all seem to get worse over time.  The last one I got arrived in December 2023, so it's about six months old.
 
I could RMA it, but since I'm at an overseas military base, it's just less of a hassle to eat the cost and buy another mouse.  Unfortunately the EVGA store on Amazon is no longer selling X15 (I'm assuming because they're super borked up and EVGA can't figure out how to fix them)

So instead of fixing their mice, eVGA has decided to just end production and stop restocking Amazon and other stores, stop replying to users for 1.5 years, bury the issue, and hope people forget about this entire product line and just pretend it never existed. If eVGA wants to burn their bridges, that's their choice. And it's my choice where my money goes for future purchases of any computer products.

Kerii7
So instead of fixing their mice, eVGA has decided to just end production and stop restocking Amazon and other stores, stop replying to users for 1.5 years, bury the issue, and hope people forget about this entire product line and just pretend it never existed. If eVGA wants to burn their bridges, that's their choice. And it's my choice where my money goes for future purchases of any computer products.

I understand. I'm sorry this has happened to you. 

rjohnson11I understand. I'm sorry this has happened to you.

There's no need for you to apologize, it's not your responsibility, it's eVGA's.
 
Since eVGA has ended this product line, I've decided to go ahead with the possible fix from this forum post:
forums.evga.com/X15Possible-Solution-Scroll-WheelDisconnectsFreezes-m3599628.aspx
 
 

 
As stated before I've already opened my mouse and inspected the solder joints, which look fine and were not disconnected, wires were not loose when prodding with a toothpick to inspect them.
However, as I have no other alternatives, I just went ahead and reflowed all three wires by the scroll wheel quickly with a fine tipped soldering iron. My X15 has not suffered any disconnects for almost a week now, whereas before it would disconnect daily, usually repeatedly every few minutes over the course of an hour. Is it poor quality solder? Is it going to disconnect again down the line? Who knows. Maybe finding some old leaded solder to replace the solder on those wires would make for a permanent solution, but for now the problem is "fixed" for me.

Kerii7but for now the problem is "fixed" for me.

How's that scroll wheel reflow holding up for you?  I reflowed all the larger solder joints on the pcb (sockets, chips, through ports, etc) and the disconnect issue remained for me - but i didn't resolder the wheel senser wires.  It happens most when first resuming the computer and seems to lessen as the mouse warms up.  It grandly dislikes being picked up off the mouse pad during that warmup period.

btarb24
How's that scroll wheel reflow holding up for you?  I reflowed all the larger solder joints on the pcb (sockets, chips, through ports, etc) and the disconnect issue remained for me - but i didn't resolder the wheel senser wires.  It happens most when first resuming the computer and seems to lessen as the mouse warms up.  It grandly dislikes being picked up off the mouse pad during that warmup period.

Worked fine for a month, then started showing a few disconnects here and there, and then finally completely flipping out and disconnecting every few seconds. I took it apart and redid the wiring and it was fine again.
Month later it happened again and I took it apart, looked carefully at it, and everything seemed fine so I just put it back together and it worked fine again.
Frankly it was a little strange that the simple act of disassembling it and reassembling it somehow "fixed" it again.
Third time now, I was expecting this, I just took the wires and wiggled them a little bit and they're fine again. I have no idea why this temporarily works. The solder connections are fine and feel stiff, there's no breakage or anything.
For the record, the original wiring and soldering seemed to be completely fine too.
Maybe I'm just bad at soldering, but that doesn't explain the original wiring which was perfectly fine too.
 
Maybe some part in the mouse is building up a charge and simply touching the components dissipates it, who knows. Whatever the case it's not a software problem, it's a proven physical defect somewhere in the mouse, because physically tinkering with it solves it, at least temporarily.