I've installed line_profiler 4.1.3 from conda and I'm using a jupyter notebook in VSCode. When I run the following cells %load_ext line_profiler def test_fn(): x = 2+2 return x lprun -f test_fn test_fn() I receive this output: Timer unit: 1e-07 s Total time: 3.8e-06 s Could not find file C:\Users\ <user>\AppData\Local\Temp\ipykernel_9076\3402019769.py Are you sure you are running this program from the same directory that you ran the profiler from? Continuing without the function's contents. Line # Hits Time Per Hit % Time Line Contents ============================================================== 1 2 1 18.0 18.0 47.4 3 1 20.0 20.0 52.6 For any function I attempt to line profile I get the same warning and I don't see any of the functions contents. This can be worked around by doing %load_ext line_profiler %%writefile test.py def test_fn() ... from test import test as t lprun -f t t() Then I get the correct output. Continue reading...