PyInstaller .exe file terminates early without an error message

Question

I have been trying to use PyInstaller to distribute my program as a bundled .exe file to my colleagues. The program, which analyses text data, runs perfectly from my CMD. I am using PyInstaller 3.6, Python 3.7, Windows 10, and Anaconda3 as my python environment. The program has quite a few dependencies including nltk, gensim, wordcloud, sklearn, matplotlib, mpld3, seaborn, pandas, numpy, xlsxwriter and a few standard libraries. It is also quite a long program, ~2000 lines.

The Problem: So far, I've successfully built the .exe file (as a one-folder and one-file bundle). To test whether the .exe file works, I run it from my CMD. All is going well (my imports and functions run OK, I am prompted to enter the name of the Excel file containing text data, the text is cleaned etc) but it abruptly terminates, without any warning or error message, on a line that uses Gensim's SparseTermSimilarityMatrix function. I experimented by commenting out this line and it terminates on the very next line, again without any message.

I am building the .exe file using a .spec file (so that I can add data files to my bundle and several hidden imports to overcome Module Not Found Errors). The only indication I have as to what is causing this problem are warnings about missing DLLs during build-time:

108890 INFO: Looking for dynamic libraries
109047 WARNING: lib not found: msmpi.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_blacs_msmpi_lp64.dll
109293 WARNING: lib not found: impi.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_blacs_intelmpi_lp64.dll
109304 WARNING: lib not found: impi.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_blacs_intelmpi_ilp64.dll
109704 WARNING: lib not found: mpich2mpi.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_blacs_mpich2_lp64.dll
109754 WARNING: lib not found: pgc14.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_pgi_thread.dll
109757 WARNING: lib not found: pgf90rtl.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_pgi_thread.dll
109761 WARNING: lib not found: pgf90.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_pgi_thread.dll
110120 WARNING: lib not found: msmpi.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_blacs_msmpi_ilp64.dll
110164 WARNING: lib not found: mpich2mpi.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Library\bin\mkl_blacs_mpich2_ilp64.dll
112452 WARNING: lib not found: icuuc53.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Scripts\Qt5Core.dll
112459 WARNING: lib not found: icuin53.dll dependency of C:\Users\username\anaconda3\envs\pyexe\Scripts\Qt5Core.dll

I would be very grateful if someone could explain:

1. Why a PyInstaller-built .exe file might terminate early without an error message - even in CMD?

2. How to address missing DLLs (which indeed I cannot find on my computer)?

UPDATE: the .exe file successfully runs from the CMD if I first activate my conda environment! conda activate [myenv] However, this defeats the purpose of a standalone distribution.

Answer 1

After realising the .exe file successfully runs from my CMD if I first activate my anaconda environment, here was my original solution, which was only suitable for a one-folder bundle:

From the root directory of my anaconda environment, I searched for all "dll" files (which returns a lot). I copied all DLL files returned by the search to the "dist" folder of my bundle, skipping duplicates.

The .exe file no longer terminated early and worked perfectly!

It seems that the warnings I received about missing DLLs during build-time were misleading - the DLL files quoted are still not on my computer.

SOLUTION UPDATE: After manually copying all DLL files from my anaconda environment to the dist folder of my bundle, I experimented by removing each DLL file I manually added one by one and testing whether the .exe file still worked or terminated early as before. It came down to just one DLL file: libiomp5md.dll - this was, quite literally, the missing link! Therefore, my recommendation:

1. search for "libiomp5md.dll" within your anaconda environment and copy it to the directory containing your .spec file
2. add it as a data file in your .spec file and specify that it should be stored in root directory of your bundle: datas=[('libiomp5md.dll', '.')]
3. Build your executable using the .spec file (either as one-folder or one-file bundle)!

I hope this helps anyone facing similar DLL-related issues.