Sorry,
but specifiying the full path did not really change it, but I am getting a more specific error at least.
Now I get
"No binary data set. So file can not be written!"
I use the node version, so no docker.
Is my approach completely wrong somewhere?
Maybe I should add what I am trying to achieve:
I am looking to pull some daily basic stats from different APIs (github, twitter, youtube …) and combine them in a table for diagrams ect. down the line.
Happy to turn this into an example node if i get it working 
{
"nodes": [
{
"parameters": {},
"name": "Start",
"type": "n8n-nodes-base.start",
"typeVersion": 1,
"position": [
220,
110
]
},
{
"parameters": {
"functionCode": "function formatDate(date) {\n var d = new Date(date),\n month = '' + (d.getMonth() + 1),\n day = '' + d.getDate(),\n year = d.getFullYear();\n\n if (month.length < 2) \n month = '0' + month;\n if (day.length < 2) \n day = '0' + day;\n\n return [day, month, year].join('.');\n}\n\nconst formattedStars = {\n date : formatDate(new Date()),\n stars : items[0].json[\"stargazers_count\"],\n}\nreturn [{json : formattedStars}];"
},
"name": "Function5",
"type": "n8n-nodes-base.function",
"typeVersion": 1,
"position": [
580,
110
]
},
{
"parameters": {
"operation": "toFile",
"fileFormat": "html",
"options": {}
},
"name": "Spreadsheet File2",
"type": "n8n-nodes-base.spreadsheetFile",
"typeVersion": 1,
"position": [
750,
110
]
},
{
"parameters": {
"options": {
"rawData": true
}
},
"name": "Spreadsheet File",
"type": "n8n-nodes-base.spreadsheetFile",
"typeVersion": 1,
"position": [
930,
110
]
},
{
"parameters": {
"fileName": "=/Users/vinckr/tmp/"
},
"name": "Write Binary File",
"type": "n8n-nodes-base.writeBinaryFile",
"typeVersion": 1,
"position": [
1100,
110
],
"notesInFlow": false
},
{
"parameters": {
"resource": "repository",
"operation": "get",
"owner": "torvalds",
"repository": "=linux"
},
"name": "GHStats",
"type": "n8n-nodes-base.github",
"typeVersion": 1,
"position": [
420,
110
],
"credentials": {
"githubApi": "n8n-github"
}
}
],
"connections": {
"Start": {
"main": [
[
{
"node": "GHStats",
"type": "main",
"index": 0
}
]
]
},
"Function5": {
"main": [
[
{
"node": "Spreadsheet File2",
"type": "main",
"index": 0
}
]
]
},
"Spreadsheet File2": {
"main": [
[
{
"node": "Spreadsheet File",
"type": "main",
"index": 0
}
]
]
},
"Spreadsheet File": {
"main": [
[
{
"node": "Write Binary File",
"type": "main",
"index": 0
}
]
]
},
"GHStats": {
"main": [
[
{
"node": "Function5",
"type": "main",
"index": 0
}
]
]
}
}
}