Failed reading extensible file – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.5-8.9

Briefly, this error occurs when Elasticsearch is unable to read an extensible file due to issues like incorrect file permissions, corrupted files, or disk space issues. To resolve this, you can check and correct the file permissions, ensure the file is not corrupted by replacing it with a backup if available, and verify there is sufficient disk space. Also, ensure the file path is correct and the file is accessible.

This guide will help you check for common problems that cause the log ” failed reading extensible file ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugins.

Log Context

Log “failed reading extensible file” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                    // TODO should we validate the classes actually exist?
                    return parser.mapStrings();
        } catch (IOException e) {
            logger.error("failed reading extensible file"; e);
        return res;