PyUSB does not seem to be properly installed one one computer about pyusb HOT 3 CLOSED

Where is usb find automatically looking for the libraries? I thought it was system32, but adding .dlls there didnt help.

That's correct. Although, technically, we delegate that to ctypes, which delegates to the OS (this can sometimes be relevant).

My first suggestion is for you to check that the DLL architecture matches the Python interpreter you're running on.

After that, use ProcessMonitor to check which paths are being tested, which files are found, etc... maybe something else is overriding the default search paths for DLLs.

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I wouldnt think the interpreter is the issue, since on the second computer I am using same python version, same interpreter. As for the process monitor suggestion, could you elaborate on that please? Could you give an example how I might I go about doing that?

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I wouldnt think the interpreter is the issue, since on the second computer I am using same python version, same interpreter.

Personally, I would check it anyway: you're already looking into a "weird" behavior, in that it works on all but one machine. At that point I think any expectations involving the word "same" are out the window... Also, the interpreter and DLLs need to be checked.

As for the process monitor suggestion, could you elaborate on that please? Could you give an example how I might I go about doing that?

As far as I remember it has a fairly intuitive interface (I don't have a Windows box at hand right now). Just open it and (IIRC) it starts to show the activity from all processes (you can also filter by process name, PID, etc).

Next, start your program—or, preferably, a minimal example that only tries to list all USB devices... import usb; usb.core.find(find_all=True)—and watch Process Monitor for what paths are accessed in one way or another.

One more thing: I'm not sure how Windows would behave if it finds a DLL with the correct name but wrong architecture in the search path. Does it keep looking for other DLLs (with that name) in (other locations in) the search path anyway, or will it only attempt to load that first, wrong, one?

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