Troubleshooting

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

Error: cannot modify limit

If you encounter the following error:

$ ulimit -n 10000
ulimit: open files: cannot modify limit: Operation not permitted

It means some system-wide configurations are preventing ulimit to being increased to a certain limit.

To override the limit:

  1. Add the following line to “/etc/security/limits.conf”:
* - nofile 10000

# '*' applies to all users and '-' set both soft and hard limits
  • The above setting may not apply in some cases, ensure “/etc/pam.d/login” and “/etc/pam.d/lightdm” have the following line. (Ignore this step if those files do not exist)
session required pam_limits.so
  1. If you are on a systemd-based distribution, systemd may override “limits.conf”. To set the limit in systemd, add the following line in “/etc/systemd/system.conf” and “/etc/systemd/user.conf”:
DefaultLimitNOFILE=10000
  1. Reboot

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

RPC failed

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.

Error: ENOENT: no such file or directory

If you get an error like Error: ENOENT: no such file or directory it’s probably due to mixing uppercase and lowercase letters in your tags, categories, or filenames. Git cannot automatically merge this change, so it breaks the automatic branching.

To fix this, try

  1. Check every tag’s and category’s case and make sure they are the same.
  2. Commit
  3. Clean and build: ./node_modules/.bin/hexo clean && ./node_modules/.bin/hexo generate
  4. Manually copy the public folder to your desktop
  5. Switch branch from your master branch to your deployment branch locally
  6. Copy the contents of the public folder from your desktop into the deployment branch
  7. Commit. You should see any merge conflicts appear that you can manually resolve.
  8. Switch back to your master branch and deploy normally: ./node_modules/.bin/hexo deploy

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 other non-JavaScript languages. 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 the older version, which shares a similar syntax). Content wrapped with {{ }} or {% %} will get parsed and may cause problems. You can skip the parsing by wrapping it with the raw tag plugin, a single backtick `{{ }}` or a triple backtick.
Alternatively, Nunjucks tags can be disabled through the renderer’s option (if supported), API or front-matter.

{% raw %}
Hello {{ world }}
{% endraw %}
```
Hello {{ world }}
```

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)

Possible cause:

  • There are some unrecognizable words in your file, e.g. invisible zero width characters.
  • Incorrect use or limitation of tag plugin.
    • Block-style tag plugin with content is not enclosed with {% endplugin_name %}
      # Incorrect
      {% codeblock %}
      fn()
      {% codeblock %}

      # Incorrect
      {% codeblock %}
      fn()

      # Correct
      {% codeblock %}
      fn()
      {% endcodeblock %}
    • Having Nunjucks-like syntax in a tag plugin, e.g. [`