After installing then UNinstalling LCC, BTT recognizes all the buttons on my MX1000.

I have an ancient but still perfectly-functional (and even still good-looking) Logitech MX1000 mouse. BetterTouchTool was handling it pretty well but did not recognize every button; it treated the forward and backward buttons (the ones just forward of and behind the scroll wheel) as scroll-up and scroll-down, just like the scroll wheel itself.

For no good reason, I installed Logitech Control Center 3.9.14 (the latest version as I write this). I never liked LCC, I used to use USB Overdrive with this mouse. I thought maybe LCC would have improved during the last 15 years – unfortunately, not much. I also learned that Logitech is dropping all support for LCC/MX1000 in Big Sur even though it works in Big Sur now. Since it wasn't a good long-term solution, and still as limited as ever anyway, I uninstalled LCC.

After running the LCC uninstaller, I restarted my Mac. Then I went back to BetterTouchTool's configuration screen and =SHAZAM= it was detecting every button on my MX1000 as a unique button. Instead of detecting those two buttons as scroll-up and scroll-down it was now detecting them as Button 6 and Button 7 – as it should. Terrific! Weird, but I don't understand how installing and then UNinstalling the LCC software should give BTT the ability to recognize buttons it could previously not distinguish from the scroll wheel.

I restarted again just to be sure and BTT continues to recognize those buttons as unique buttons 6 and 7.

So I don't get it, but perhaps this will be helpful to someone else with an ancient mouse like mine which wasn't playing 100% perfectly with BTT. Regardless of the reason, I'm happy I can now use BTT to assign different functions to those two buttons instead of having them function as a duplicate scroll wheel.

great, thanks for sharing! I knew that the logitech software writes configuration data to the mouse, but I didn’t know it configures the buttons to act as standard buttons.

You said, "writes configuration data to the mouse". That's interesting! I assume you mean it writes configuration data to some file somewhere. Do you know what that file is named and where it is located? In the future, with some new Mac with "Apple Silicon" which won't be able to run the Logitech Control Center in order to perform this trick, it would be nice to be able to drop that file into place so that my non-creaky creaky old mouse will still be able to be fully functional with BetterTouchTool.

no it writes directly to the memory of the mouse. So no file and I assume the mouse now behaves like this on all computers you connect it to.

Wow, really? Even more interesting! I am not able to test on another computer (at least, not anytime soon) but I can set up a different boot volume on my Mac and test it that way. Thank you for your replies!

I have a Mojave boot volume on an external drive. I booted from that, installed BetterTouchTool there (and imported my license file), and it recognized all of the buttons on my Logitech MX1000 mouse. I have a spare MX1000 and I pulled that out. After shutting down my primary MX1000 and pairing the spare with the mouse's base station I checked it in BetterTouchTool and some of this mouse's buttons are NOT recognized as unique by BTT – just as my primary MX1000 behaved before I ran Logitech Control Center while the mouse was connected to my Mac.

I had no idea that the Logitech Control Center utility wrote to the memory of the mouse – I wasn't even aware that the mouse had memory! I thought every button generated a unique ID which was then just handled by software.

Anyway, very interesting, and it's nice to know that my most favorite mouse will be fully usable for as long as I can make it last without any need to keep some file backed up.

A little more testing with this:

1- I moved my mouse (and its "base station" – the Logitech MX1000 is a wireless mouse that connects to the computer with a USB cradle which is also its charger) to another computer and the settings remained. You were of course correct: The settings are written to the mouse itself.

2- When I installed Logitech Control Center on that other computer, the settings created in LCC were used instead of the "raw" mouse button values my mouse was generating before I installed LCC on that computer. LCC can only assign mouse button values up to "8" and this mouse needs 9. This seems to be because it treats the scroll wheel/middle button as "Middle Mouse" and never as a numerical value, at least within its own UI display.

3- However, when I uninstalled LCC from that computer, the mouse again generated the desirable "raw" values so that each one could be recognized as unique by BetterTouchTool. I then repeated these tests with my backup Logitech MX1000 mouse (and its own base station) and got the same results.

So based on (2) and (3) I would suggest that, when dealing with a Logitech mouse which requires LCC in order to get BTT to recognize all its buttons; that LCC be installed, run once, then uninstalled rather than being left in place as its drivers seem to get in the way of BTT fully recognizing all the buttons. And LCC is no longer necessary once it writes those "raw" values to the mouse buttons, which it seems to do as part of the uninstall process (at least, that's how it appears to me based on my testing).

We had a brief power outage at my home yesterday. When I brought my computer back up, I noticed that my MX1000 mouse was back to its default settings – nothing changed in BetterTouchTool, I'm talking about the ID of the various mouse buttons. For example, Button 6 and Button 7 which are the buttons just above and below the scroll wheel were back to being recognized by BTT as Scroll Up and Scroll Down; and Button 8 and Button 9 which are the left/right scroll wheel tilt buttons were back to being recognized by BTT as Scroll Left and Scroll Right.

So I booted into Mojave (I usually boot into Big Sur but LCC is no longer "supported" for Big Sur), installed Logitech Control Center, and checked the button ID detection in BTT – no change. I uninstalled LCC and as soon as that was done but BEFORE restarting (LCC tells you to restart in order to complete the uninstallation) and BTT detected those buttons as 6, 7, 8, 9. After that check I restarted into Mojave and BTT continued to recognize those buttons as 6, 7, 8, 9. I then booted back into Big Sur and BTT recognized those buttons as 6, 7, 8, 9 – as I want it to.

So two things:
1- Whatever LCC is writing to the memory of the mouse does not survive a power off. I have tested and discovered that I can switch the mouse on and off and the button IDs will not get reset. But if the mouse's base station – which relies on AC power – experiences a power failure either purposely because I pull the plug or from a blip in my house AC supply, the mouse's button IDs get reset back to their defaults. This might be a peculiarity of my very old Logitech MX1000 mouse and its RF base station but it might be true of other Logitech mice as well.
2- Whatever LCC does to set the buttons on the mice it can control from whatever that mouse's defaults might be to standard button IDs (that is, from something like SCROLL LEFT to BUTTON 8) happens during the UN-installation process, not during installation nor while LCC is running and assigning functions to the mouse buttons.

Maybe I'm the only person who still uses an old Logitech mouse. If so, sorry to take up space here. But perhaps this will be helpful to someone else.