When the G502 was first released, I was one of the first people to post on the forum about it and said it was the best mouse sensor ever released. I had installed the mouse, put in my settings, and uninstalled the software when I first got it. A week later I decided to reinstall the software to change button binds on the mouse and from that point on, I could NEVER get the mouse to feel remotely as good as when I first reviewed it. Profile 3 would also do strange things like revert to 500hz even though I set it to 1000hz, but the other two profiles didn't do it.
Today I randomly decided to try and debug the issues with this mouse and remembered a long time ago that a Steelseries mouse I used, I think it was the Xai, had major issues when I set both profiles to the exact same settings, 800 DPI and 1000hz and all three of my G502 profiles were set to the same thing. I decided to go all out making sure I did every possible step to debug this mouse and it finally worked and it's back to being the best sensor out again. Here's the steps I did:
1) First, enable the Human Interface Device service if it's disabled. Reboot the computer if it was disabled, if it was already running, proceed to step two. (you can disable it again after all this is over if you want)
2) If the G502 is not currently plugged in, power off the PC, unplug the current mouse, then plug in G502.
3) If the G502 was already plugged in, or if you have ever plugged it in before on your current windows install, then you need to go in device manager and uninstall whichever "USB Composite device" corresponds to your mouse in the list as shown below, then reboot. If you guess the wrong one and uninstall both, sometimes Windows will not install either on reboot, then you have to physically unplug them and plug them back in. It always works if you only uninstall one though, so just do it again until you get it right.
4) You will see a "installing device" balloon pop up in the bottom right corner on Win7 or in the bottom taskbar on Win8 after doing the above step. This balloon only pops up the first time you ever plug a new mouse in on your current Windows install, so you're forcing Windows into doing this over again, then you should reboot after it happens.
5) Install Logitech software, if surface tuning was on anything but default, change it back to default.
6) Go in the first profile. Click the "restore defaults" button. Change "DPI sensitivity levels" to 1, then input what DPI you want by highlighting the DPI number and type your DPI in with the keyboard and hit enter, do not move the sliders or arrows to set DPI. Next, do the same thing with the other two profiles, but do not input the same DPI setting as the first profile. If profile 2 or 3 is already on the same setting that you just changed profile 1 to, then you will need to go back and redo profile 1 after you set profile 2 and 3 to something else. Your main DPI setting that you use should be profile 1 as well. Do not bother trying to disable profile 2 or 3, when I did before, they get bugged and either refuse to turn off or refuse to turn back on. The software is buggy, that's why you're going through all these steps.
7) Don't change any settings like light effects or anything else in the options menu for Logitech software, just reboot your PC now.
8) The Logitech software is going to automatically start now. Click the Logitech options menu and basically uncheck all the boxes in it so that it doesn't start on Windows boot or do any of the other irrelevant things in there, then reboot the PC after.
9) Wait a minute or two for Windows to settle, then manually open Logitech Gaming Software and you will see the light logo on the mouse flash when it does as it reinitializes the mouse. At this point, your mouse should be working properly and you should exit Logitech software and reboot the PC again. After reboot, the software should not have started, and at this point, if you feel like the sensor is performing better than any sensor you've used, you should go into the program manager, uninstall the software, and never go near it again. Also, uninstall Apple Bonjour.
Today I randomly decided to try and debug the issues with this mouse and remembered a long time ago that a Steelseries mouse I used, I think it was the Xai, had major issues when I set both profiles to the exact same settings, 800 DPI and 1000hz and all three of my G502 profiles were set to the same thing. I decided to go all out making sure I did every possible step to debug this mouse and it finally worked and it's back to being the best sensor out again. Here's the steps I did:
1) First, enable the Human Interface Device service if it's disabled. Reboot the computer if it was disabled, if it was already running, proceed to step two. (you can disable it again after all this is over if you want)
2) If the G502 is not currently plugged in, power off the PC, unplug the current mouse, then plug in G502.
3) If the G502 was already plugged in, or if you have ever plugged it in before on your current windows install, then you need to go in device manager and uninstall whichever "USB Composite device" corresponds to your mouse in the list as shown below, then reboot. If you guess the wrong one and uninstall both, sometimes Windows will not install either on reboot, then you have to physically unplug them and plug them back in. It always works if you only uninstall one though, so just do it again until you get it right.
4) You will see a "installing device" balloon pop up in the bottom right corner on Win7 or in the bottom taskbar on Win8 after doing the above step. This balloon only pops up the first time you ever plug a new mouse in on your current Windows install, so you're forcing Windows into doing this over again, then you should reboot after it happens.
5) Install Logitech software, if surface tuning was on anything but default, change it back to default.
6) Go in the first profile. Click the "restore defaults" button. Change "DPI sensitivity levels" to 1, then input what DPI you want by highlighting the DPI number and type your DPI in with the keyboard and hit enter, do not move the sliders or arrows to set DPI. Next, do the same thing with the other two profiles, but do not input the same DPI setting as the first profile. If profile 2 or 3 is already on the same setting that you just changed profile 1 to, then you will need to go back and redo profile 1 after you set profile 2 and 3 to something else. Your main DPI setting that you use should be profile 1 as well. Do not bother trying to disable profile 2 or 3, when I did before, they get bugged and either refuse to turn off or refuse to turn back on. The software is buggy, that's why you're going through all these steps.
7) Don't change any settings like light effects or anything else in the options menu for Logitech software, just reboot your PC now.
8) The Logitech software is going to automatically start now. Click the Logitech options menu and basically uncheck all the boxes in it so that it doesn't start on Windows boot or do any of the other irrelevant things in there, then reboot the PC after.
9) Wait a minute or two for Windows to settle, then manually open Logitech Gaming Software and you will see the light logo on the mouse flash when it does as it reinitializes the mouse. At this point, your mouse should be working properly and you should exit Logitech software and reboot the PC again. After reboot, the software should not have started, and at this point, if you feel like the sensor is performing better than any sensor you've used, you should go into the program manager, uninstall the software, and never go near it again. Also, uninstall Apple Bonjour.