WinXP Driver not installing

Hi all,

just bought me a 12 channel Mini Maestro.
I am unable to install the software driver.
I have to admit I plugged in the modul before installing the software.

Now I can install the software but if I plug in the device and do the new hardware installation as recommanded it is not installing anything. even if I point it to the driver location where I have the software unpacked “D:\Download\Pololu\maestro_windows\drivers” it does not find any drivers to install although there are the file maestro.inf and pololu_usb_to_serial.inf.
I also checked the usbser.sys, it is version 5.1.2600.5512.
Any ideas? suggestions?
Maybe this one hardware plugin before installing the software did something wrong?


Hello, Vern.

I am sorry you are having trouble with your Maestro. After unpacking the Maestro zip file, you should run setup.exe. Have you done that?

After running setup.exe, the rest of the instructions in the “Installing Windows Drivers and Software” section of the Maestro user’s guide should work for you.

Also, do you have the latest version of the drivers ( To be sure, you should download it from our website as described in those instructions.


Hi David,

thanks for the answer.
I downloaded the software from your website today, it is the latest.
I did everything what is says in the instructions, except that i plugged the board into the usb port before installing the driver.
But it was unplugged when i installed the software.
Anyway, i installed everything on a second computer (WinXP SP2) and voila: it runs.
But i would like it installed on my first machine, because that is where i’m doing my stuff.
So i keep digging.
Is it possible that the usbser.sys file is somehow buggy? to new?


Regarding your other computer: Please note that the USB-to-serial drivers for the Maestro will not work properly with Windows XP SP2.

When people have trouble with their drivers I usually ask them to follow the procedure below for Windows XP. It sometimes works and sometimes gives a more informative error message. Please try the following:

  1. Go the Device Manager. You can get there by right-clicking on My Computer and selecting Manage and then selecting Device Manager.
  2. Locate the entry that says Pololu Mini Maestro 12-Servo Controller. It should be under “Other Devices” or “Pololu USB Devices”. If it is in the “Pololu USB Devices” category and there are no warning indicators (e.g. a yellow circle with an exclamation point) on the icon for it, then it is probably installed correctly, but it is OK to do this procedure anyway.
  3. Right-click on it and select “Update Driver…”
  4. Choose “No, not this time.” and click “Next”.
  5. Choose “Install from a list or specific location.” and click “Next”.
  6. On the next screen, tell windows to “Search for the best driver in these locations” and point it to the folder where the Maestro drivers are installed. This should be the folder where the installer put maestro.inf. It should be “C:\Program Files\Pololu\Maestro\drivers” if you installed the software in the default place. Please let me know if you have to choose a folder other than that one. The “Search for the best driver in these locations” radio button and the “Include this location in the search” checkbox should both be checked. Click “Next”.
  7. If everything goes well, Windows will work for a few minutes and tell you that it installed the drivers successfully. If something different happens, please take a screenshot of the message you see and post it here. You can upload the picture as an attachment.