In case you’re experiencing problems with using Hexo, here is a list of solutions to some frequently encountered issues. If this page doesn’t help you solve your problem, try doing a search on GitHub or our Google Group.

YAML Parsing Error

JS-YAML: incomplete explicit mapping pair; a key node is missed at line 18, column 29:
      last_updated: Last updated: %s

Wrap the string with quotations if it contains colons.

JS-YAML: bad indentation of a mapping entry at line 18, column 31:
      last_updated:"Last updated: %s"

Make sure you are using soft tabs and add a space after colons.

You can see YAML Spec for more info.

EMFILE Error

Error: EMFILE, too many open files

Though Node.js has non-blocking I/O, the maximum number of synchronous I/O is still limited by the system. You may come across an EMFILE error when trying to generate a large number of files. You can try to run the following command to increase the number of allowed synchronous I/O operations.

$ ulimit -n 10000

Process Out of Memory

When you encounter this error during generation:

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory

Increase Node.js heap memory size by changing the first line of hexo-cli (which hexo to look for the file).

#!/usr/bin/env node --max_old_space_size=8192

Out of memory while generating a huge blog · Issue #1735 · hexojs/hexo

Git Deployment Problems

error: RPC failed; result=22, HTTP code = 403
fatal: 'username.github.io' does not appear to be a git repository

Make sure you have set up git on your computer properly or try to use HTTPS repository URL instead.

Server Problems

Error: listen EADDRINUSE

You may have started two Hexo servers at the same time or there might be another application using the same port. Try to modify the port setting or start the Hexo server with the -p flag.

$ hexo server -p 5000

Plugin Installation Problems

npm ERR! node-waf configure build

This error may occur when trying to install a plugin written in C, C++ or another non-JavaScript language. Make sure you have installed the right compiler on your computer.

Error with DTrace (Mac OS X)

{ [Error: Cannot find module './build/Release/DTraceProviderBindings'] code: 'MODULE_NOT_FOUND' }
{ [Error: Cannot find module './build/default/DTraceProviderBindings'] code: 'MODULE_NOT_FOUND' }
{ [Error: Cannot find module './build/Debug/DTraceProviderBindings'] code: 'MODULE_NOT_FOUND' }

DTrace install may have issue, use this:

$ npm install hexo --no-optional

See #1326

Iterate Data Model on Jade or Swig

Hexo uses Warehouse for its data model. It’s not an array so you may have to transform objects into iterables.

{% for post in site.posts.toArray() %}
{% endfor %}

Data Not Updated

Some data cannot be updated, or the newly generated files are identical to those of the last version. Clean the cache and try again.

$ hexo clean

No command is executed

When you can’t get any command except help, init and version to work and you keep getting content of hexo help, it could be caused by a missing hexo in package.json:

{
  "hexo": {
    "version": "3.2.2"
  }
}

Escape Contents

Hexo uses Nunjucks to render posts (Swig was used in older version, which share a similar syntax). Content wrapped with {{ }} or {% %} will get parsed and may cause problems. You can wrap sensitive content with the raw tag plugin.

{% raw %}
Hello {{ sensitive }}
{% endraw %}

ENOSPC Error (Linux)

Sometimes when running the command $ hexo server it returns an error:

Error: watch ENOSPC ...

It can be fixed by running $ npm dedupe or, if that doesn’t help, try the following in the Linux console:

$ echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

This will increase the limit for the number of files you can watch.

EMPERM Error (Windows Subsystem for Linux)

When running $ hexo server in a BashOnWindows environment, it returns the following error:

Error: watch /path/to/hexo/theme/ EMPERM

Unfortunately, WSL does not currently support filesystem watchers. Therefore, the live updating feature of hexo’s server is currently unavailable. You can still run the server from a WSL environment by first generating the files and then running it as a static server:

$ hexo generate
$ hexo server -s

This is a known BashOnWindows issue, and on 15 Aug 2016, the Windows team said they would work on it. You can get progress updates and encourage them to prioritize it on the issue’s UserVoice suggestion page.

Template render error

Sometimes when running the command $ hexo generate it returns an error:

FATAL Something's wrong. Maybe you can find the solution here: http://hexo.io/docs/troubleshooting.html
Template render error: (unknown path)

It means that there are some unrecognizable words in your file.There are two possibilities One is your new page/post, and the other one is _config.yml.
In _config.yml, don’t forget add whitespace before a list in hash. There is the wiki page about YAML.
The error one:

plugins:
- hexo-generator-feed
- hexo-generator-sitemap

The correct one:

plugins:
  - hexo-generator-feed
  - hexo-generator-sitemap