The Xbox 360 controller has been popular since its launch in 2005, even after its follow-up controller launched in 2013. Why? Because it's one of the best "it just works" gaming pads for PCs.

After third-party solutions forced the issue, Microsoft eventually continued the "it just works" tradition in 2014 by launching official, perfectly solid drivers for the Xbox One controller. That tradition looked like it would live on this week with the rollout of another updated Xbox One controller model, complete with a new Bluetooth radio.

After some investigating, however, Ars Technica has bad news for PC gamers who just want to get their Xbox One pads working on their favorite games. Whether you use a new Bluetooth controller or you upgraded your old XB1 to this week's Windows 10 Anniversary edition, get ready for some road bumps.

XInput marks the spot?

Before we dive in, a note: we have sent questions to Microsoft about our concerns and about the technical reasons for these issues. The answers may very well hint at upcoming patches or fixes, which could render our complaints moot.

We hope so, because the clock is ticking for Xbox One controller issues on Windows: T-minus seven weeks. On September 27, Microsoft Studios and Turn 10 will release Forza Horizon, the first in a wave of "Play Anywhere" games meant to launch simultaneously on Xbox One and Windows 10. Forza Horizon will likely bring a lot of attention to Windows 10.

That being said, the primary compatibility issue is wreaking havoc on various PC games whose controller support used to work just fine. Some games no longer recognize when Xbox One controllers are connected via Bluetooth or through the official Xbox One wireless adapter. Other games, as well as Steam's Big Picture mode, think a single Xbox One controller is two controllers simultaneously.

The number and type of games affected at this point appears to be scattershot, with an official Xbox support forum thread cataloging various errors. In our own experience, Windows 10's Anniversary update definitely changes something with both launch-edition Xbox One pads and the updated, Bluetooth-enabled pads that launched this week. Installing the Windows 10 Anniversary update caused our Xbox One pads to briefly sync with our PC's Xbox One wireless adapter, then automatically power down.

Only when we attempted a full re-sync did the controllers once again register, which required the installation of a brand-new controller driver for each re-synced pad. At that point, certain controller-friendly games, like Gang Beasts and Videoball, stopped recognizing our Xbox One pads. At least our wired Xbox 360 pads continued to work as they had before.

Has the Xbox One controller's use of the XInput API been altered? XInput, after all, is the API that ushered in the Xbox 360 pad's wide PC acceptance. Game makers just slapped the API into their games to enable easy, no-fuss controller compatibility (which both 360 and XB1 pads utilize). Many other controllers play nicely with that API, though homebrew efforts also exist to turn on "exclusive" mode and remap other controllers to the XInput API.

We point this out because Windows 10's Anniversary update also broke current homebrew ways to get popular controllers, like Sony's DualShock 4, to play with Windows PCs. There's currently a hack to get DualShock 4 pads working on Windows 10 with the Anniversary update, but the dev behind InputMapper, the most popular DS4 workaround for Windows PCs, says that the hack "does not fix the underlying issue."

A patch or update to the currently broken XB1 controller driver could very well fix whatever Microsoft did in the Anniversary update. But that still doesn't explain why the controller driver required an update in the first place, let alone what Microsoft is doing that disables the compatibility of other controllers.

Bluetooth might make gamers blue

Another issue is less likely to receive an update: the new Xbox One controllers' Bluetooth support is severely limited. As in, only one pad can be connected via Bluetooth at once.

Microsoft isn't advertising this limitation, but an official Xbox Support page confirms it: you can only connect one Bluetooth pad to a Windows 10 PC at a time, and those Bluetooth pads require running on Windows 10 with the Anniversary update. If you want to use more wireless Xbox One pads on a single PC, you'll need to purchase the official Xbox One wireless adapter. Otherwise, don't rush out and buy a bunch of updated Xbox One pads expecting them to sync up to any laptop for the sake of wild, on-the-go multiplayer sessions of Push Me Pull You or Towerfall: Ascension.

The situation gets worse. Your sole Bluetooth controller won't even function in Windows 10's Anniversary update until you update the controller's firmware, which users aren't told when they connect the pads. Instead, users must manually find and install the Xbox Accessories app from the Windows Store. Boot that with the Xbox One pad connected via Bluetooth, and you'll then get the prompt to update the pad's firmware. The new Xbox One controller does not include instructions to this effect, possibly because Xbox One consoles automate this process in a way that Windows 10 PCs do not.

Until Microsoft announces an update to these controller-based woes, the gaming geeks at Ars recommend that you avoid the Anniversary update. If you've already updated and want to return to the "it just works" days of XInput support on wireless controllers, toggle to the "revert to your previous install of Windows" option, which isn't hard to find in the options menus.

Update, 8/10: On Tuesday, a Microsoft representative confirmed that the Xbox engineering team was working on issues with controllers' "exclusive" modes, controller connectivity with certain games, and Steam Big Picture mode seeing two controllers where there should be only one. No timeline was given for fixes on those issues. The Microsoft rep also insisted that two of the new-hardware Xbox One gamepads should be able to connect simultaneously to a single Windows 10 PC via Bluetooth, so long as both controllers have their firmware updated. The company's support site still lists a one-pad limit when connecting via Bluetooth. We are awaiting a response about that discrepancy.