Describe the problem/error/question
Hi everyone,
I’m facing a persistent issue with the Read/Write Files from Disk node (v1.1) when trying to execute a “Write File to Disk” operation. It consistently throws an error stating that the file is not writable, regardless of the folder, user permissions, or execution mode.
My Environment:
- n8n Version: 2.26.4 (Self Hosted)
- Execution Mode: Tested both on native Windows (Node.js setup) and via Docker Desktop (WSL2 backend).
- Database Mode: Tested with both binaryDataMode: filesystem and binaryDataMode: database.
What I’ve tried so far:
- Native Windows: Targeted local folders (C:\n8n\poema.json) and temporary paths. Got the “not writable” error.
- Docker (Standard User): Mounted volume -v c:/n8n:/data and targeted /data/poema.json. Fails.
- Docker Isolated Path: Tried writing directly into Docker container native paths like /tmp/poema.json and /home/node/poema.json. Fails with the exact same error.
- Pre-creating the file: I manually created an empty poema.json file (0 KB) inside the destination folder to check if it was a creation vs update issue. Still throws “not writable”.
- Docker Root User: Recreated the container forcing the root user (-u root) to bypass any potential host/container permission conflicts on the mounted volume. The behavior persists.
Error Stack Trace:
{
"errorMessage": "The file \"/data/poema.json\" is not writable.",
"errorDetails": {
"rawErrorMessage": [
"The file \"/data/poema.json\" is not writable."
]
},
"n8nDetails": {
"nodeName": "Read/Write Files from Disk",
"nodeType": "n8n-nodes-base.readWriteFile",
"nodeVersion": 1.1,
"operation": "write",
"itemIndex": 0,
"n8nVersion": "2.26.4 (Self Hosted)",
"stackTrace": [
"NodeApiError: The file \"/data/poema.json\" is not writable.",
" at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-nodes-base@file+packages+nodes-base_@aws-sdk+credential-providers@3.808.0_asn1.js@5_8da18263ca0574b0db58d4fefd8173ce/node_modules/n8n-nodes-base/nodes/Files/ReadWriteFile/actions/write.operation.ts:130:10)"
]
}
}
Given that this happens even inside /tmp/ within a container running as root, it looks like a false negative in the node's internal validation logic (specifically around write.operation.ts:130).
Is this a known regression in v2.26.x or is there any specific environment variable I should tweak to fix this validation check?
Thanks in advance for your help!
## What is the error message (if any)?
{
"errorMessage": "The file "/data/poema.json" is not writable.",
"errorDetails": {
"rawErrorMessage": \[
"The file "/data/poema.json" is not writable."
\]
},
"n8nDetails": {
"nodeName": "Read/Write Files from Disk",
"nodeType": "n8n-nodes-base.readWriteFile",
"nodeVersion": 1.1,
"operation": "write",
"itemIndex": 0,
"n8nVersion": "2.26.4 (Self Hosted)",
"stackTrace": \[
"NodeApiError: The file "/data/poema.json" is not writable.",
" at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-nodes-base@file+packages+nodes-base\_@aws-sdk+credential-providers@3.808.0_asn1.js@5_8da18263ca0574b0db58d4fefd8173ce/node_modules/n8n-nodes-base/nodes/Files/ReadWriteFile/actions/write.operation.ts:130:10)"
\]
}
}
## Please share your workflow
The workflow is a simple 3-node structure:
HTTP Request ➡️ Convert to File ➡️ Read/Write Files from Disk (Write operation).
The Convert to File node outputs binary data successfully (approx. 27.5 kB), but the execution stops completely at the Read/Write Files from Disk node.
## Share the output returned by the last node
I'm facing a persistent issue with the Read/Write Files from Disk node (v1.1) when trying to execute a "Write File to Disk" operation. It consistently throws the "is not writable" error, regardless of the folder, user permissions, or execution mode.
What I've tried so far to isolate the issue:
1. Native Windows: Targeted local folders (C:\n8n\poema.json) and temporary paths. Got the error.
2. Docker (Standard User): Mounted volume -v c:/n8n:/data and targeted /data/poema.json. Fails.
3. Docker Isolated Path: Tried writing directly into Docker container native paths like /tmp/poema.json and /home/node/poema.json. Fails with the exact same error.
4. Pre-creating the file: I manually created an empty poema.json file (0 KB) inside the destination folder to check if it was a creation vs update issue. Still throws "not writable".
5. Docker Root User: Recreated the container forcing the root user (-u root) to bypass any potential host/container permission conflicts on the mounted volume. The behavior persists.
Given that this happens even inside /tmp/ within a container running as root, it looks like a false negative in the node's internal validation logic (specifically around write.operation.ts:130).
## Information on your n8n setup
* **n8n version:**
* **Database (default: SQLite):**
* **n8n EXECUTIONS_PROCESS setting (default: own, main):**
* **Running n8n via (Docker, npm, n8n cloud, desktop app):**
* **Operating system:**
* n8n Version: 2.26.4 (Self Hosted)
* Database: SQLite (default)
* Execution Mode: Regular (and tested via Docker / WSL2 backend)
* Binary Data Mode: database (also tested with filesystem)