---
title: "Single-cell RNA Sequencing — Troubleshooting"
canonical: "https://build.nvidia.com/playbooks/single-cell/troubleshooting.md"
---

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| Symptom | Cause | Fix |
|---------|-------|-----|
| Docker is not found. | Docker may have been uninstalled, as it is preinstalled on your DGX Spark | Please install Docker using their convenience script here: `curl -fsSL https://get.docker.com -o get-docker.sh && sudo sh get-docker.sh`. You will be prompted for your password. |
| Docker command unexpectedly exits with "permissions" error | Your user is not part of the `docker` group | Open Terminal and run these commands: `sudo groupadd docker && sudo usermod -aG docker $USER`.  You will be prompted for your password.  Then, close the Terminal, open a new one, and try again |
| Docker container download, environment build, or data download fails | There was either a connectivity issue or a resource may be temporarily unavailable. | You may need to try again later. If this persists, please post on the Spark user forum for support |

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> [!NOTE] 
> DGX Spark uses a Unified Memory Architecture (UMA), which enables dynamic memory sharing between the GPU and CPU. 
> With many applications still updating to take advantage of UMA, you may encounter memory issues even when within 
> the memory capacity of DGX Spark. If that happens, manually flush the buffer cache with:
```bash
sudo sh -c 'sync; echo 3 > /proc/sys/vm/drop_caches'
```

For latest known issues, please review the [DGX Spark User Guide](https://docs.nvidia.com/dgx/dgx-spark/known-issues.html).