When running conan install -u while no previous conan install was run (so e.g. no conan conanbuildinfo.cmake exists) I get the following traceback:

I can't reproduce the error. Do you have a conanfile.py? conanfile.txt? Windows right?
It's Windows, yes. Conan version is 0.10.1. I have a simple repo with a simple conanfile.txt like this:
[requires]
googlemock/1.7.0@image/stable
Qt/5.7.0@image/stable
[generators]
cmake
[imports]
bin, *.dll -> ./bin # Copies all dll files from the package "bin" folder to my project "bin" folder
When I create a new folder and run conan install -u {SOURCE_DIR} I always get the shown traceback.
Actually, the Qt / short_paths.conf might be the culprit. I have tried with a different repository that does not have a Qt dependency (and thus, does not use short_paths.conf) and it is working properly.
Have you modified the short_paths.conf? Could you paste here?
There is one entry in my short_paths.conf for the Qt package:
Qt/5.7.0@image/stable: C:/Qt/5.7.0/image/stable
I get it. I've opened a PR #391 solving it, It will be fixed in next release
I am also preparing a new (hopefully better) solution for the short paths limit, #392
Nice to hear. Let me know in case I can help with testing.
This has been released in 0.11. Please upgrade and re-open if necessary. Thanks!