Dealing with “Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: error mounting ”/foo/bar/data.json“ to rootfs at ”/app/data.json“: mount src=/foo/bar/data.json, dst=/app/data.json, dstFd=/proc/thread-self/fd/11, flags=MS_BIND|MS_REC: not a directory: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type”

2 Feb 2026 2 mins Docker

I recently spent great amount of time dealing with the error Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: error mounting "/foo/bar/data.json" to rootfs at "/app/data.json": mount src=/foo/bar/data.json, dst=/app/data.json, dstFd=/proc/thread-self/fd/11, flags=MS_BIND|MS_REC: not a directory: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type. I guess I’ll share and maybe this will save some time to somebody.

This was a container that expects /app/data.json file and my docker-compose.yml contains - /foo/bar/data.json:/app/data.json:ro so everything should be working. But it wasn’t. Here are the steps I did and you can guess where I made the mistake.

I started the container. Initially the /foo/bar/data.json was not present, you know, go raw, go big, go default. That created /foo/bar/data.json directory. OK, time to fix that. I deleted the directory and created a file. Start container. Same error. Time to double check. Yes, it is a file, and it is where it is supposed to be. Start container again. Same error. Am I crazy? Tripple check. Yep, all looks good. What’s going on?

Can you guess?

Of course, the problem was between the chair and the keyboard. I did not recreate the container; I was still starting the original one. Quick docker rm ... and docker compose up -d and everything was working. The Are you trying to mount a directory onto a file (or vice-versa)? threw me completely to a wrong path, because I was though it somehow still sees the old directory.

Lesson learned. And if you’re reading this, I hope it saves you some time.

Jiří Činčura is .NET, C# and Firebird expert. He focuses on data and business layers, language constructs, parallelism, databases and performance. For almost two decades he contributes to open-source, i.e. FirebirdClient. He works as a senior software engineer for Microsoft. Frequent speaker and blogger at www.tabsoverspaces.com.