# Project compilation failed (error code: 2) **URL:** \ **Category:** Support\ **Created:** [13 November 2025 03:27 UTC](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507 "2025-11-13T03:27:12Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![danielmk](https://yyz2.discourse-cdn.com/free1/user_avatar/brian.discourse.group/danielmk/32/661_2.png) [@danielmk](https://brian.discourse.group/u/danielmk)\ **Post date:** [13 November 2025 03:27 UTC](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507/1 "2025-11-13T03:27:12Z")
# Description of problem My cpp\_standalone compilation capabilities broke. Not sure what I did to break it. Maybe it was the Windows11 update? I get the error `RuntimeError: Project compilation failed (error code: 2), consider having a look at 'winmake.log'.` Brian2 version is 2.9.0 Python is 3.11.14 # Minimal code to reproduce problem ```python import brian2 as b2 b2.set_device('cpp_standalone', build_on_run=False) net = b2.Network() tau = 10*b2.ms G = b2.NeuronGroup(2, "dv/dt = (1-v)/tau : 1") net.add(G) net.run(1*b2.second) b2.device.build(run=False, directory=None, clean=True) ``` The complete output: ```auto INFO No numerical integration method specified for group 'neurongroup', using method 'exact' (took 0.03s). [brian2.stateupdaters.base.method_choice] --------------------------------------------------------------------------- RuntimeError Traceback (most recent call last) Cell In[1], line 8 6 net.add(G) 7 net.run(1*b2.second) ----> 8 b2.device.build(run=False, directory=None, clean=True) File ~\miniforge3\envs\sbilab\Lib\site-packages\brian2\devices\cpp_standalone\device.py:1630, in CPPStandaloneDevice.build(self, directory, results_directory, compile, run, debug, clean, with_output, additional_source_files, run_args, direct_call, **kwds) 1620 self.generate_makefile( 1621 self.writer, 1622 compiler, (...) 1626 debug=debug, 1627 ) 1629 if compile: -> 1630 self.compile_source(directory, compiler, debug, clean) 1631 if run: 1632 self.run(directory, results_directory, with_output, run_args) File ~\miniforge3\envs\sbilab\Lib\site-packages\brian2\devices\cpp_standalone\device.py:1162, in CPPStandaloneDevice.compile_source(self, directory, compiler, debug, clean) 1156 if not clean: 1157 error_message += ( 1158 " Consider running with " 1159 '"clean=True" to force a complete ' 1160 "rebuild." 1161 ) -> 1162 raise RuntimeError(error_message) 1163 else: 1164 with std_silent(debug): RuntimeError: Project compilation failed (error code: 2), consider having a look at 'winmake.log'. ``` The winmake.log ends on ```auto synapses_classes.cpp NMAKE : fatal error U1073: don't know how to make 'sourcefiles.txt' Stop. ``` I can provide the full winmake.txt if that helps. # What you have aready tried I created a new environment but it did not help. I checked my Visual Studio Build Tools. I have Visual Studio Build Tools 2022. I have installed: - C++ Build Tools core features - MSVC v143 - VS 2022 C++ x64/x86 build tools (Latest) - Windows 10 SDK - Windows 11 SDK - C++ CMake tools for Windows - C++ core features - Windows Universal CRT SDK And a bunch of other stuff that I think is irrelevant to Brian2. # Expected output (if relevant) # Actual output (if relevant) # Full traceback of error (if relevant) ---
**Author:** ![mstimberg](https://yyz2.discourse-cdn.com/free1/user_avatar/brian.discourse.group/mstimberg/32/11_2.png) [@mstimberg](https://brian.discourse.group/u/mstimberg)\ **Post date:** [13 November 2025 08:53 UTC](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507/2 "2025-11-13T08:53:39Z")
Hi @danielmk, this is odd indeed! Could you please share the generated `win_makefile` and `sourcefiles.txt`? ---
**Author:** ![danielmk](https://yyz2.discourse-cdn.com/free1/user_avatar/brian.discourse.group/danielmk/32/661_2.png) [@danielmk](https://brian.discourse.group/u/danielmk)\ **Post date:** [14 November 2025 02:18 UTC](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507/3 "2025-11-14T02:18:31Z")
Thanks for the quick reply @mstimberg This is the win\_makefile: ```auto all: main.exe clean: del *.obj /s del *.exe /s del sourcefiles.txt code_objects\neurongroup_stateupdater_codeobject.obj: win_makefile cl /c /EHsc /I. -I"C:\Users\Daniel\miniforge3\envs\sbilab\Library\include" /Ox /w /arch:AVX2 /MP code_objects/neurongroup_stateupdater_codeobject.cpp /Focode_objects\neurongroup_stateupdater_codeobject.obj main.obj: win_makefile cl /c /EHsc /I. -I"C:\Users\Daniel\miniforge3\envs\sbilab\Library\include" /Ox /w /arch:AVX2 /MP main.cpp /Fomain.obj network.obj: win_makefile cl /c /EHsc /I. -I"C:\Users\Daniel\miniforge3\envs\sbilab\Library\include" /Ox /w /arch:AVX2 /MP network.cpp /Fonetwork.obj objects.obj: win_makefile cl /c /EHsc /I. -I"C:\Users\Daniel\miniforge3\envs\sbilab\Library\include" /Ox /w /arch:AVX2 /MP objects.cpp /Foobjects.obj run.obj: win_makefile cl /c /EHsc /I. -I"C:\Users\Daniel\miniforge3\envs\sbilab\Library\include" /Ox /w /arch:AVX2 /MP run.cpp /Forun.obj synapses_classes.obj: win_makefile cl /c /EHsc /I. -I"C:\Users\Daniel\miniforge3\envs\sbilab\Library\include" /Ox /w /arch:AVX2 /MP synapses_classes.cpp /Fosynapses_classes.obj main.exe: code_objects\neurongroup_stateupdater_codeobject.obj main.obj network.obj objects.obj run.obj synapses_classes.obj win_makefile sourcefiles.txt link @sourcefiles.txt /LIBPATH:"C:\Users\Daniel\miniforge3\envs\sbilab\Library\lib" advapi32.lib /LIBPATH:. /OUT:main.exe ``` I don’t know where sourcefiles.txt is. It’s not in `brian_standalone_` ---
**Author:** ![mstimberg](https://yyz2.discourse-cdn.com/free1/user_avatar/brian.discourse.group/mstimberg/32/11_2.png) [@mstimberg](https://brian.discourse.group/u/mstimberg)\ **Post date:** [14 November 2025 14:34 UTC](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507/4 "2025-11-14T14:34:49Z")
Hmm, well this explains the error. There _should_ be a `sourcefiles.txt` file in the same folder as the `win_makefile`. I think there is a bug when you use `clean=True` on Windows. From the makefile, it seems that `clean` deletes `sourcefiles.txt` which I think it shouldn’t. Could you try running it without `clean=True`? Building the code with `clean=True` is meant to call something `make clean && make` instead of a simple `make`. But if `make clean` removes a file that is necessary for the following `make`, this is not going to work… ---
**Author:** ![danielmk](https://yyz2.discourse-cdn.com/free1/user_avatar/brian.discourse.group/danielmk/32/661_2.png) [@danielmk](https://brian.discourse.group/u/danielmk)\ **Post date:** [16 November 2025 02:57 UTC](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507/5 "2025-11-16T02:57:14Z")
Without `clean=True` the minimal code and my actual simulator work now. I actually only added `clean=True` because I got a RuntimeError almost identical to the one I described above, but it told me to add `clean=True` because that might resolve the issue. So I added it, but it did not resolved the issue. Then I setup a completely new environment. I guess that solved the issue I originally had, but `clean=True` introduced a different issue. Anyway, my simulator works again on Windows, but I guess I discovered a bug with `clean=True`