6 JSON output could not be parsed
Moritz Bunkus edited this page 2021-02-05 23:06:55 +00:00

The GUI states "JSON output generated by mkvmerge could not be parsed"

Adding a file in the GUI popups up an error message similar to the following ones:

error message about JSON output #1 error message about JSON output #2

Error executing mkvmerge

The JSON output generated by mkvmerge could not be parsed (parser's error
message: parse error - unexpected `[`; expected end of input).
Error executing mkvmerge

The JSON output generated by mkvmerge could not be parsed (parser's error
message: parse error - unexpected `m`).

Possible solution 1: blocked by Anti Virus programs

Several users have reported such a case, and in each case it was due to their Anti Virus program blocking or interfering with mkvmerge.exe.

Please configure your Anti Virus solution to exempt mkvmerge.exe from scanning. It's located in the MKVToolNix installation folder. Then delete the MKVToolNix cache directory (make sure MKVToolNix GUI isn't running). Last start the GUI and try the operation again.

Possible solution 2: versions of mkvmerge the GUI differ

MKVToolNix GUI and mkvmerge must always be the same version. You cannot run the e.g. GUI v9.7.1 with mkvmerge v9.4.2. Verify that the mkvmerge and mkvtoolnix-gui executables located in the same folder have the same version number.

On Windows that version number can be found in the files' properties:

executable version details on Windows

On all operating systems you can compare the version numbers output by both programs. Here's an example for Linux:

/usr/bin/mkvmerge --version
/usr/bin/mkvtoolnix-gui --version

Possible solution 3: the cache is corrupted

Before deleting the cache folder, first make sure MKVToolNix GUI isn't running anymore. Then locate the cache folder and simply delete it. Then try adding the file(s) again.

Categories: debugging