Symptoms

When typing a German Umlaut (like höher) in Quick Search,  the umlaut character is translated to another symbol, for example: h�her

See sample screen shot:

Diagnosis

• Temporarily enable Plugin Safe Mode and see if it makes any difference. This will disabled all user-installed plugins at once. So if the issue does not occur again, it is caused by one of the third-party plugins installed. This may need to be done during non-peak hours as disabling third-party plugins would cause users unable to perform some operations provided by those plugins. Once the test has been carried out, disable this mode.

• Check on the followings against your Confluence setting and see if it is already set to utf-8 or otherwise:

  • Application Server URL encoding
  • Confluence server encoding
  • Database encoding

Cause

This is caused by RefinedWiki Theme 

Resolution

Upgrade the plugin to the latest version that is compatible with your Confluence version. If problem remains, disable/uninstall Refined Wiki Theme and contact the plugin author for further assistance at:

support@refinedwiki.com
https://refinedwiki.atlassian.net/browse/RWOT