# How to fix OSError: libcudart.so.11.0: cannot open shared object file: No such file or directory

Your torch build wants CUDA 11.0 but the loader cannot find its libraries. Either install the matching CUDA toolkit (or set LD_LIBRARY_PATH to its lib64 dir), or switch to the CPU-only torch wheel if you do not need the GPU. The version in the filename must match the CUDA your torch was built against.

## The exact error

```text
OSError: libcudart.so.11.0: cannot open shared object file: No such file or directory
```

## Fix it

1. Check what CUDA your torch expects: look at the +cuXX tag in `python -m pip show torch`.
   Expected: e.g. cu110, cu118, cu121

2. Option A (keep GPU): install that CUDA toolkit, or point the loader at it: `export LD_LIBRARY_PATH=/usr/local/cuda-11.0/lib64:$LD_LIBRARY_PATH`.
   Expected: `import torch` no longer raises the OSError

3. Option B (no GPU needed): `pip install torch --index-url https://download.pytorch.org/whl/cpu`.
   Expected: torch imports and runs on CPU

## When this applies

`import torch` (or torchvision/torch_geometric) fails with `libcudart.so.X` / `libcudnn` / `libtorch_cuda` not found on Linux

## When this does NOT apply

Windows DLL errors or `No module named 'torch'`

## Versions

Linux, CUDA builds of torch

## Why it happens

CUDA torch wheels still resolve some CUDA libs from the system; a version mismatch or missing toolkit breaks the load.

## Edge cases

nvidia-smi showing CUDA 12.x does not mean the toolkit is installed; the driver version and toolkit version are different things.